VMS RED SERIES CCR. User Manual

Transcription

1 VMS RED SERIES CCR User Manual Version:

2 This is the operations manual for the: VMS RED SERIES of Rebreathers (referred to as the unit in this document unless otherwise specified) include: VMS Sentinel RedHead VMS RedBare This manual, specifications and features of the VMS Red Series, are the property of Vobster Marine Systems Ltd This document cannot be copied or distributed without the prior agreement and authorisation of Vobster Marine Systems Ltd. All information contained is subject to change, contact us for the latest version, or visit These units are manufactured in the UK by: Vobster Marine Systems Ltd Vobster Quay Upper Vobster Radstock Somerset BA3 5SD United Kingdom tel : EN14143:2013 Excluding Section (See section on Hydrostatic Imbalance) EC Type approved by SGS UK Ltd. Weston-Super-Mare. BS22 6WA. Notified Body No Tests Conducted by ANSTI Test Systems Ltd, Hants, UK and HSL Labs Buxton UK. Page 1 Vobster Marine Systems Ltd version: 1.5.2

3 Cautionary Statement... 5 Section 1: The VMS RED SERIES Orientation... 7 An introduction to Life Support Systems and rules of operation... 7 VMS RED SERIES operational limits and rules of operation... 8 RED SERIES improvements over previous CCR LSS designs... 8 External features VMS Sentinel RedHead External features VMS RedBare Under the cover Gas Flow and analysis Electronic systems Filter performance and monitoring Rules for CCR LSS diving Hydrostatic Imbalance Section 2: Electronic anatomy Introduction Design Criteria Turning on: Introduction to system status Automatic safety turn on Surface Status Screen Display Screen and Menu Tree HUD Normal dive states HUD/ Alarm states PO2 States...22 Valve States...23 Filter States...23 Battery States...24 HP Diluent States...24 HP O2 States...24 Deco States...24 Misc States...25 Co2 Systems Temperature Profile Monitor (TPM)...26 Metabolic Rate Counter (MRC)...27 Timer...27 Page 2 Vobster Marine Systems Ltd version: 1.5.2

4 PO2 module CO2 Sensor isec functions Section 3: Physical anatomy Design Criteria The Breathing Loop Units with a BOV (Bail out Valve)...33 Units with DSV (Diver Selection Valve)...34 The Mouthpiece and Hoses Mouthpiece Retaining Strap...37 Head, flowcone, filter and body Analysis chamber Counterlung Gas Block ADV housing Solenoid Plug and play cables Harness and BCD Cylinders Over pressure valve Section 4: Rebreather function while diving Normal dive function, no error states O2 HP failure DIL HP failure Solenoid failure ADV failure Gas leaks Absorbent failure O2 Sensor failure Sources of incorrect O2 readings...47 Multiple Sensor failure...48 Rogue sensors...48 CO2 Sensor failure and false reading Primary screen failure Main battery failure Use of isec Section 5: Setup for diving Preparation for first dive Calibration of O2 and CO2 sensors Flow check Loop Integrity Analysis of Gas Gauges Stack filling and function Page 3 Vobster Marine Systems Ltd version: 1.5.2

5 Battery charging Weighting Harness Positioning Section 6: Operational configuration Diluent selection Gas Endurance Bailout selection LSS gas programming Primary handset programming...60 ISEC programming...60 Setpoint Selection Auto setpoint changes Setpoint changes: ascents & descents CCR Dive planning functions OC Bailout planning ADV use Section 7: PreDive check sequence Step by step confirmation of unit readiness Shortened check availability Section 8: Troubleshooting Cell mv readings Mouthpiece and flow check fail issues Loop negative - leak detection HP Sensor malfunctions HP / LP Gas leaks TPM reading failure Section 9: Mandatory Diving Skills Section 10: Care and Maintenance Immediately post dive End of day Weekly or end of trip Prior To Storage Every 100 Hours Every 12 Months Every 24 Months or 200 Dive hours Absorbent Storage and Handling Page 4 Vobster Marine Systems Ltd version: 1.5.2

6 Cautionary Statement The VMS RED SERIES CCR s are Type approved to the EN 14143:2013 standard. Despite the sophistication of the design and testing, the following conditions and warnings apply to any use of the VMS RED SERIES CCR LSS. Use outside these conditions has not been tested to achieve CE rating and use outside these conditions is excluded from warranty support. THE UNIT IS WARRANTED FOR USE TO A MAXIMUM DEPTH OF 100 M SEAWATER. THE WATER TEMPERATURE RANGE FOR USE OF THE UNIT IS 4 C TO 34 C THE MAXIMUM DEPTH FOR ANY DIVE IS DETERMINED BY THE DILUENT. VMS STIPULATE THE USE OF TRIMX DILUENTS BELOW 39 M. THE DILUENT MIX FOR A 100 M DIVE SHOULD NOT CONTAIN MORE THAN 10% OXYGEN AND NOT LESS THAN 80% HELIUM. THE DILUENT SHOULD NEVER CONTAIN LESS THAN 5% OXYGEN ONLY USE DIVING GAS MIXTURES THAT COMPLY WITH BS EN 12021:2014 ASCENT RATES SHOULD NOT EXCEED 10 M PER MINUTE THE WORK OF BREATHING IS MINIMISED WHEN THE DIVER IS NEAR PRONE WITH NO ROLL. THE WORK OF BREATHING WILL INCREASE WHEN THE DIVER IS VERTICALLY HEAD DOWN, OR LYING ON THEIR BACK AND BREATHING HARD (above 40 l/min). THE UNIT HAS COMPLETED ALL TESTING USING MOLECULAR PRODUCTS 797 SOFNOLIME. DO NOT USE OTHER BRANDS OR SPECIFICATIONS OF SOFNOLIME. ONLY VMS O2 CELLS SHOULD BE USED IN THIS UNIT, AS THEY ARE MADE SPECIFICALLY FOR IT. CARBON DIOXIDE ENDURANCE During CE testing the Unit achieved the following minimum results for carbon dioxide endurance: 100m - 47 minutes (using 10/80 diluent) 40m minutes (using an air diluent) This is the breakthrough time to 5 mb of CO2 in 4 degrees of water, at a breathing rate of 40 l/min and a CO2 injection rate of 1.6 l/min. These tests simulate particularly harsh conditions to give a guide to the minimum durations that can be expected. However, the Red Series CCR are fitted with 3 types of CO2 measurement / monitoring (Metabolic Rate Counter, TPM and CO2 Sensor). Using these to monitor your filter, will allow you to safely achieve a total duration of up to 4 hours, particularly when the unit is used at shallower depths, in warmer temperatures or with lower metabolic/work rates (so for example if you are using a scooter / DPV for propulsion). The Unit uses high pressure O2 to enable the maintenance of safe oxygen levels while diving. This presents the potential risk of an Oxygen fire, which could cause serious injury or death. To mitigate this risk, all parts that come into contact with high pressure O2 are cleaned and tested to Oxygen clean standards, including the O2 cylinder, valve and first stage. It is important that these parts are maintained in this state by having your unit and cylinders cleaned and serviced Page 5 Vobster Marine Systems Ltd version: 1.5.2

7 at the recommended service intervals, or if you suspect that the system has been contaminated. Care should always be taken when handling high pressure O2. CNS (Central Nervous System Oxygen Toxicity) is a combination of oxygen pressure and time. Your training will cover CNS oxygen toxicity and the exposure limits. Prolonged exposure to oxygen in excess of 0.5 bar can lead to pulmonary toxicity, affecting the whole body. Pulmonary toxicity is tracked using OTU s (Oxygen Toxicity Units). One OTU is defined as breathing 100% oxygen at one bar for one minute. The most conservative limit sets a maximum of 300 OUT s per day for multi day diving trips. You can view the OTU s for your previous dive by viewing the dive logs. These should be totalled if you are doing multiple dives per day. By purchasing a VMS CCR and reading this manual, you acknowledge that diving in general and CCR diving specifically, are inherently dangerous activities. You acknowledge that these machines require unit specific training to minimise these risks, and that the choice to dive the Unit can only be made by you and the responsibility for all consequences of diving the Unit always lies with the diver. Your Unit is provided with a mouthpiece Head Strap. This is provided to minimise the risk of drawing should you fall unconscious underwater. VMS strongly recommend that you use this whenever you are underwater. Page 6 Vobster Marine Systems Ltd version: 1.5.2

8 Section 1: The VMS RED SERIES Orientation Congratulations on your purchase of your VMS RED SERIES unit, a CCR designed from the bottom up for advanced exploration, robustness, reliability and ease of support in remote locations. The suite of high performance rebreather functions and fully integrated life support monitoring sets our units in a separate class from other rebreathers. An introduction to Life Support Systems and rules of operation Closed Circuit Life support systems scrub the diver s exhaled gas clean of exhaled carbon dioxide and then optimally replenish with O2 before the gas is re-breathed. The primary benefit of this is reducing the waste of gas bubbled away, still containing useful Oxygen, that occurs in open circuit systems. The balance is that closed circuit systems have different hazards and risks that require knowledge, understanding, training and attention to detail to avoid. These sophisticated operational features and configuration options are implemented into a simple to dive unit with particular attention given to reducing task loading via Head Up Display notification of system status. Application to remote dive operations is further boosted by simple in field fault finding and component replacement. This creates major benefits for all remote users, from high technology recreational divers through to government agencies operating major scientific and archaeological projects. The main components of the system are: Closed circuit breathing loop to provide breathable gas to the diver and in the process remove carbon dioxide from the diver s exhaled gas. High-pressure Oxygen cylinder to allow addition of oxygen into the breathing loop to compensate for oxygen used by the diver s metabolism. High pressure Diluent gas cylinder with low oxygen content to dilute the oxygen and maintain loop PO2 at a non-toxic pressure. The diluent gas can be air for depths up to 39 m, depending on certifying agency. Below this, Helium is added to the gas and the oxygen percentage lowered. Electronic and mechanical control systems to facilitate the addition of oxygen into the breathing loop to maintain a breathable and optimised oxygen level. Integrated monitoring systems for resource levels such as cylinder contents, filter temperature, CO2 levels and battery charge level. Calculation of decompression obligation for closed and open circuit operation. Dive range and safety can be further extended via the use of off board gasses and the units off board connection system, with additional hot swappable external diluent mixes. In keeping with a philosophy of reliability, safety and diving style variance, these units can also function completely without the main electronics computer system. They incorporate an Independent Secondary Page 7 Vobster Marine Systems Ltd version: 1.5.2

9 (isec) PO2 display system that shows the mv and normalised PO2 reading for each cell. This provides an alternative and/or backup system that gives the diver adequate information on which to perform or complete a mission, manually controlling the setpoint through the manual O2 addition valve. This unit also calculates decompression requirements based on these in loop values independent of the main computer and represents an optimal level of backup to the computer. These features and functionality are reinforced by the diver support services of Vobster Marine Systems. VMS RED SERIES operational limits and rules of operation Use of your unit must ALWAYS comply with the following: 1) Unit assembly must be as described in this manual. 2) Unit calibration of O2 and CO2 sensors must be done as described in this manual. 3) Always pre breathe the unit until system is green. 4) CO2 filter material must not be reused, repacked or reactivated in any way. 5) High pressure Diluent and O2 cylinders must contain sufficient gas for the planned dive. 6) The CE testing for these units is to 100 m. Dives beyond this depth cannot be warranted. 7) The recommended gas for this depth (100 m) is that used for CE testing and is maximum 10% Oxygen with a minimum of 80% Helium. 8) VMS recommends that trimix diluents are used on all dives deeper than 39 m. 9) Always carry sufficient OC bailout as per training agency recommendations for your planned dive. 10) All gasses must be analysed and marked before diving. 11) The water temperature for the planned dive should lie between 4 degrees and 34 degrees Celsius. 12) WOB evaluations and test results for these units are only valid for units in manufactured configuration. Aftermarket alterations to configuration or counterlung housing do not comply with the CE test conditions. 13) Never start a dive with a known fault or alarm condition active. 14) Do not leave mouthpiece open at the surface. 15) Always inflate your BCD at the surface. 16) Ensure you are correctly weighted for your dive - NEVER dive over weighted. 17) Practice a skill on each dive and conduct post dive debrief of system performance. 18) Take time to ensure your knowledge of rebreather controls, both electronic and manual is complete RED SERIES improvements over previous CCR LSS designs The VMS RED SERIES design for the LSS incorporates several improvements over previous industry designs, including features evolved from the Sentinel Expedition rebreather. 1) CO2 filter duration, monitoring and flood recovery: The unit has a proven EN tested scrubber duration that exceeds all similar units. Coupled with this is a metabolic rate counter, thermal profile monitor and timer that combine to give excellent information to the diver on scrubber duration remaining during normal operation or advance warning of impaired scrubber performance, enabling safe retreat before OC bailout is the only option. Page 8 Vobster Marine Systems Ltd version: 1.5.2

10 2) PO2 tracking: A full redesign of PO2 sampling regime has enabled tuning of O2 injection to respond to the demands of both varying depth and diver ventilation scenarios. The result is an accurate, rapid response by the system to PO2 variation from depth or metabolism. PO2 variation at 100 m has now been consistently tracked within.004 Bar of Setpoint. 3) CO2 monitoring: Your VMS RED SERIES unit is a sport CCR rebreather with the most robust, reliable CO2 monitoring system, enabled in part by the hotter filter temperatures providing a gas sampling environment with less moisture. Water droplets are easily confused with CO2, providing inaccurate reporting of CO2 levels. The reliable system in the unit enables diver confidence of actual in loop CO2, instead of estimations from indirect algorithms and assumptions, or reliance on unreliable human detection. 4) Low mechanical work of breathing - Gas movement around the loop is powered by the breath of the diver. This energy requirement from the diver should be minimised to reduce CO2 load on the CO2 filter. The silicone valves, large bore hoses, integral protected back mounted counterlung of the unit all reduce the breathing resistance and hence work of breathing to as low as 0.5 Joules per litre at 100 m. 5) Redundant systems increasing mission flexibility and safety - The safety concept of the LSS is to ensure that no single failure of electrical or electronic or programmable electronic device or system will cause failure of the complete system. 6) Modular, light weight, field serviceable design - removable PO2 module, electronics pod, handsets and plug n play cable connections for CO2, buddy HUD, diver HUD and handsets combine with molded head to provide simple component exchange, simpler shipping and lighter airline transport. 7) Advanced electronic LSS configuration: Full control over all system components is given to the diver to enable fault finding, acknowledgement and operational decision making. This control also allows the greatest level of dive flexibility and offers several levels of controlled failure before OC bailout is required. 8) Safety Design Criteria and FMECA analysis of CCR Incidents: Functional Safety as set out in IEC and related safety issues have been of particular importance in designing the VMS RES SERIES LSS. Of particular relevance has been the considerable diver input on types of failure and user error within LSS systems, both in the mechanical and control systems. From this direct hands-on information, safety systems within the unit are higher than on any other current LSS. On top of this, safety design has been the driving force behind your unit, to be as forgiving as possible to diver error, and to component failures. 9) Loop flood recovery via base mounted over pressure valve. Many of these features, such as filter performance, PO2 stability and CO2 analysis also support each other to give a system that gives overall performance greater than the sum of it s parts. Page 9 Vobster Marine Systems Ltd version: 1.5.2

11 External features VMS Sentinel RedHead 1. Weight Pocket 2. Inhale Hose 3. Exhale Hose 4. Case Latches 5. Wing 6. DIL cylinder 7. Back Case 8. Oxygen cylinder 9. Back plate 10. Primary Handset 11. O2 Gas block 12. DIL Gas block 13. Secondary Handset 14. Wing inflate Page 10 Vobster Marine Systems Ltd version: 1.5.2

12 External features VMS RedBare 1 Inhale hose 2 Exhale hose 3 Cover 4 Diluent Cylinder 5 Oxygen Cylinder 6 Steal frame 7 Cylinder Cam Bands 8 Buddy Hud 9 Exhale Hose 10 Inhale Hose 11 Counter Lung 12 Primary Handset 13 Gas Blocks 14 Wing Inflator 15 Mouthpiece 16 Primary Hud Page 11 Vobster Marine Systems Ltd version: 1.5.2

13 Under the cover Gas Flow and analysis A typical journey of gas flow around the units loop begins with: 1) Inhalation by the diver of gas from the inhale counterlung, via the one way valve on the mouthpiece. This has just been verified by O2 and CO2 sensors as being both safe to breath and with a setpoint appropriate to the dive at that point. 2) Upon exhalation this gas has less O2, more CO2 and importantly more moisture. The gas travels via the one way valve into the exhale hose. Page 12 Vobster Marine Systems Ltd version: 1.5.2

14 3) The exhale hose delivers the gas into the top of the flow cone, where the gas passes into and downwards through the CO2 filter. 4) The CO2 filter accomplishes removal of CO2 from this gas via a chemical absorption process. This process leaves the gas with little or no CO2. 5) The gas travels up around the outside of the filter to a chamber containing three O2 cells and the CO2 cell, plus a port to the inhale countering and exit to the inhale hose. 6) The O2 cells each report PO2 to the main computer. The computer compares the readings with each other and with the setpoint specified for the dive at that point. If the measured PO2 has dropped 0.01 bar, the solenoid is opened ( fired ) to inject a small amount of Oxygen. This injection is before the CO2 filter, making the analysed gas homogenous and less liable to error. Errors in analysis from non mixed gas, sensor differences or moisture impairment of sensor surface cause injection errors and PO2 variation. PO2 variation on CCR is the equivalent of bouncing on OC and makes inert gas loadings more complex. Multiple cells also allow voting logic to be applied to isolate rogue cells as well as redundancy in case of cell failure. 7) At this point, gas volume is also balanced between the divers lungs and the CCR using the counterlung. This flexible bag is required to contain volume displaced by exhalation of the lungs. It is placed on the inhale side, not exhale to ensure that gas reaching the filter does not lose heat and therefore water vapour through condensation, increasingly CO2 filter efficiency. 8) Under normal rebreather function, gas will not stray outside safe breathable parameters. If the analysis indicates gas properties outside dive parameters at this point, the LSS will alert the diver via a blue green alternating LED on the HUD for a low level or manageable error or red flashing LED and buzzing alert for a non breathable loop. This ensures that the diver is always aware of the breathable status of their next breath. 9) Inhalation returns the scrubbed and replenished gas to the diver via the inhale one way mushroom valve. Page 13 Vobster Marine Systems Ltd version: 1.5.2

15 Electronic systems The VMS RED SERIES CCR comprises the following systems which monitor resources, control O2 injection and provide information on dive parameters, gas parameters and system status to the diver / buddy. 1) PO2 cells (primary and backup), CO2 cell, HP gas levels for O2 and DIL, Filter TPM and main battery status. Where resource sensors have independent battery supply (TPM and PO2 cells, these battery readings are also incorporated into the system self monitoring status updates. 2) The LSS has three means of relaying status to the diver and one for the buddy: 3) The diver HUD has four LED s, the combination of which summarises system and dive status. A solid green LED indicates that all enabled systems are functioning and gas is within selected dive parameters. An alternating Blue Green indicates a manageable system error or low level deviation from gas parameters. Attention to the primary display will inform the diver of details. A flashing red and buzzer requires immediate bailout to open circuit due to critical system failure or non breathable gas. 4) Diver HUD functionality is mirrored by the buddy HUD mounted behind the divers head on the exhale hose 5) The Primary handset on the Left wrist displays dive details and allows control over all system features. Decompression information is based on in loop FO2 and diluent information 6) The Independent SECcondary (ISEC) handset displays the individual cell PO2 readings, but can be switched to display dive information, with decompression based on in loop FO2 via an independent data pathway from the cells. System features cannot be isolated or enabled from this handset, but diluents and OC bailout gasses can be switched. These sensor readings are independently calibrated. 7) Buttons on both handsets have two function modes: Short push and Long push. This allows the following combinations to access different functions from any one screen: Short push right Short push left Long push Right Long push Left Short push both Long push both Not all these combinations are used on every screen. A function key appears at the bottom of each screen, with Long push functions identified with a thick bracket and short push functions with a thin bracket. Page 14 Vobster Marine Systems Ltd version: 1.5.2

16 Filter performance and monitoring The VMS RED SERIES continues to use the combination of filter function monitors pioneered to the recreational market by the Sentinel Expedition. This monitoring system comprises four parts 1) Chemical scrubbing activity of the CO2 filter is confirmed pre dive and monitored during the dive by a Thermal Profile Monitor (TPM). This rod of eight thermistors indicates both the level of activity and changing profile during the dive, displayed on the handset in status screens. Reduction in heat generated triggers an alarm indication, giving early warning of filter material failure or flooding. It is an indirect method to confirm gas breathability. 2) CO2 monitor: Gas is analysed post CO2 filter by the infrared CO2 monitor. This independent confirmation of filter performance provides direct measurement of next inspired breath. 3) Metabolic rate counter (MRC): The filter contains 2.25 kg of filter material, which can be converted into a known capacity for CO2 removal. The CO2 in the system is only produced by the diver from injected O2. The MRC tallies amount of injected O2, converting this into a maximum possible amount of CO2 produced and compares this to the known CO2 capacity of the filter. When that value is reached, an alarm is triggered. This provides a bespoke calculation of maximum filter life remaining, automatically compensating for decreased filter capacity through high metabolic rate exercise. 4) Timer: The unit will automatically indicate that filter is likely to be exhausted after five hours of runtime Each of these components has a threshold value that triggers either a Blue Green or Red alarm. Any Red alarm will supersede an existing Blue Green alarm. Typically, a loss of comms on these components is a Blue Green, while High CO2, low Temp or Timer expired will trigger a Red alarm. A full list of alarm codes can be found in the Alarm states section. Together, these CO2 monitoring methods provide the most sophisticated assessment of remaining filter life available to any CCR diver. Rules for CCR LSS diving 1) Always ensure your unit is fully functioning before a dive. Complete PreDive checks and achieve a solid screen status before entering the water. Do not start a dive with a known fault. 2) Always know your PO2. Do not let your diluent PO2 exceed your setpoint. 3) Always monitor yourself for physiological signs of hypoxia, hyperoxia and hypercapnia. The unit is a sophisticated CCR with multiple monitors, but remain self alert at all times. 4) Ensure all resources are adequate for planned dive: battery levels, O2 and DIL pressures, filter time remaining and CO2 sponge is dry. 5) Ensure all gasses, MOD and setpoints are programmed into both handsets. 6) Check wing inflator, bladder and dumps are all operating correctly. 7) Ensure gasses are consistent with advice in manual and from training agency for planned dive. Do not exceed your certification level. Carry enough OC gas for a safe bailout ascent. 8) Ensure you are personally dive fit for the planned dive. 9) Ensure you are correctly weighted with all required equipment. Do a check dive. 10) Always do a skill on every dive 11) Always investigate and clear alarms - do not continue to dive with an unresolved alarm causing alarm blindness to possible further malfunctions. 12) Red alarm means bailout, check PO2. Only return to the loop if PO2 and CO2 levels are safe to breathe. Page 15 Vobster Marine Systems Ltd version: 1.5.2

17 13) Know your machine, the unit is equipped with many features that are designed to help keep you safe, but also to enable you to make decisions and take action. The better your understanding of these features and their function, the safer you will be. 14) If in doubt, ask. The unit has an excellent support network from both your instructor and VMS direct. Advice and clarification is always available - please use it to stay current and stay safe. Hydrostatic Imbalance What is hydrostatic imbalance? In simple terms hydrostatic imbalance is the effect you feel on your lungs due to the fact that the rebreather you are breathing from (including the counter lung/s) is in a different position in the water column than your lungs. So for example if you dive with a counter lung that is below you in the current diving orientation you will feel a positive pressure due to the fact that the counter lung is at a higher pressure than you are. Conversely if the counter lung is above you, you will experience a negative pressure as the counterlung will be at a lower pressure than you are. The measurement of this difference (compared to what you would feel on the surface) is measured in milli bars and is called the Hydrostatic Imbalance. Clearly as you change orientation in the water, the hydrostatics will also change, and for CE purposes the acceptable range of this change is +/- 20 mb. There are two valves that will also come into play if you change orientation, which are the ADV and OPV, one adding gas if the hydrostatic pressure is too low, and the other venting gas if it is too high. These operate at the extreme ends of the range, as fine control is achieved by the diver. The VMS RED SERIES do not meet section of the EN14143:2013 standard. The unit does not pass on the +180 (lying on back position), or -90 (head down position) if the ADV is active, as the pressure is artificially increased due to the ADV firing (as it is below you in these orientations). Should you need to operate in these orientations you simply need to isolate the ADV (using the slider on the gas block), and maintain your loop volume manually. The units do however comply in all other orientations.. Page 16 Vobster Marine Systems Ltd version: 1.5.2

18 Section 2: Electronic anatomy Introduction The electronics and computer systems have been designed to provide a system with: - Sophisticated multi resource monitoring to warn of low resource or component failure - At a glance information and ease of use - Automatic and manual override modes of operation - Modularity - Reliability Careful design and testing ensures this comprehensive monitoring system is simple to use in normal operation, when the diver is not over burdened with too much information or controls. It also provides detailed status information, to perform more complex maintenance or emergency procedures. Design Criteria The electronics and computer systems have been designed around five main criteria: 1) Safety: The reliability of the system underwater in providing a breathable gas and feedback in the system operations are of paramount importance. Although the diver would routinely carry backup and have bailout contingency plans, the system wherever possible should provide a breathable gas in as extreme an environment as is feasible. 2) Reliability: Significant effort has been made to contain physical damage to electronic components, leaving alternate LSS control or monitoring pathways intact and useable. The following features make the VMS RED SERIES extremely damage resistant: 1. External cables are double sheathed, with each of eleven cores having an O ring on the terminating pin at each end. These cables are plug and play - they do not penetrate into sealed electronic spaces, limiting flood damage to control systems. Internal side of these bulkheads are also potted to eliminate the last possibility of water ingress. 2. Internal data transfer from PO2 module and TPM is via infrared link, with no cable penetration into electronic spaces, or cables to be damaged during unit assembly. 3. Both handsets and main electronics pod are double O ring sealed and dived three times to 100 m before leaving VMS. This confirms their integrity as a unit and individually. 4. Cable routing has been redesigned to reduce the chance of accidental damage. 3) Redundancy : Should any of the front facing displays fail, the in-board control system will maintain the life support functions, even if control functionality is reduced. If a severed cable results in loss of PO2 or external readings, then this will be alarmed for on the active displays and appropriate action can be take using backup systems. In case of main system failure, the redundancy in providing independent backup information allows the trained diver to manually control the system and get out of the water safely. 4) Maintenance / Serviceability: Battery, oxygen partial pressure cell and system status are provided to the diver, so that these can be changed when the levels fall below design limits. Maintenance itself is simple, and reduces pre/post service/maintenance times. 5) Modularity: The electronics systems are designed to allow a dive to continue with all or only parts of the available systems connected. For example the unit will still function with or without the following items: - Head Up Display (HUD) - High Pressure (HP) sensors - Rear facing HUD - Primary Display - Backup Display On top of this, different diving styles can also be accommodated. For example only the HUD can be used for diving, with the Primary display or PC link only used for initial system setup. This style has been adopted for some military or other minimal clutter diving missions. Page 17 Vobster Marine Systems Ltd version: 1.5.2

19 This robust approach to component damage or failure DOES NOT mean a dive should be started with a known fault or damage. These features are intended to allow a mission or dive to be aborted on the CCR when the loop remains breathable, instead of the poorer option of open circuit bailout. DO not start a dive with a known fault. 6) Simplified in field troubleshooting and resolution: The modular approach of the RED SERIES means that fault identification can be achieved via simple rapid component swapping. Once identified as faulty, components can be exchanged with spares with no factory visit and faulty components returned alone for assessment and repair. These smaller returns are significantly easier to ship. The VMS RED SERIES LSS exists in a single version state allowing component swapping between units without software or functionality conflicts impairing the troubleshooting process. This modularity and consistency also allows prudent divers the chance to take a platinum triage kit on important expeditions. This kit will contain spares of significant components such as electronics pod, PO2 module, primary and ISEC handsets, preventing costly dive delays or shipping difficulties with replacement components to remote locations. If your dive program cannot afford these delays, please contact VMS for details of our field backup Platinum Triage service. Don t leave home without it. Turning on: Introduction to system status The VMS RED SERIES can be turned on manually using a long push of both buttons on the primary handset until you see the VMS logo. At this point the initial SURFACE STATUS screen will be displayed. At first turn on, no pre dive has been completed, resulting in a RED HUD and NO DIVE warning. The next step from here is to enter PREDIVE. This PREDIVE sequence must be aborted to enable further screens to be accessed. The abort sequence will warn of the dangers of not completing predive before immersion and lead back to the surface status screen. Access to further screens is via the menu tree described below. If the unit is not required, a short press of both buttons leads to the Sensor status screen, where a further long push of both buttons activates the OFF mode. In this dormant mode, the unit continues to monitor PO2. Page 18 Vobster Marine Systems Ltd version: 1.5.2

20 Automatic safety turn on. Normal practice and training is for the user to turn the LSS on manually and complete the pre-dive checks. The following failsafe additions are to reduce diver error, where the LSS is turned off prior to breathing on the unit. The basis for the auto-breathe software is to reduce the chance of accidental death by breathing on a LSS that is in off/sleeping state. This has happened in several cases. The common method to reduce the likelihood of this is to have contacts that turn the unit on when it is wet. This is good for surface swimming. However, a chamber or non-wet use of the LSS may occasionally occur. Wet contacts can also reduce battery life in wet environments. Hence this detection of a PO2 drop (assumed to be breathing) is an improvement to the wet contact system as it covers most cases of accidental use when the LSS is currently off and when a person forgets to turn the LSS on before breathing on the system. The cost of this PO2 monitoring is the power consumption required to routinely monitor PO2. The sampling rate and resulting power consumption has been redesigned to achieve an optimal balance. Breathing detection turn on rules: 1) If PO2 <0.17 bar and > 0.05 bar. If cells are removed or read 0.00 then the unit will only turn on with depth or by the user pressing a switch. This has to be done to conserve battery power when the user takes out PO2 cells for storage or during transport. Current other LSS designs and CE approvals require a reduced safety margin than achieved even with this power save scenario. In other words, the chance of the user taking out the cells and accidentally not turning the unit on before breathing falls into user set-up error that should not routinely occur due to training and a good pre-dive check regime. Other errors of no turn on of hp, etc. are much more likely, and should be reduced by proper training and the intelligent alarm systems. 2) Turn on if PO2 dropped more than 0.05 bar in 1 minute. This is adequate for even light breathing on the loop. If the unit has just been dived, in normal use, the PO2 in the loop will be 0.40 bar or greater. Hence even after a 0.05 bar drop, the loop will still be breathable. If there is only 0.21 bar in the loop, eg. if only air in loop, then the unit will turn on due to item 1 above, still with headroom for PO2 alarms before hypoxia. If the diver does not have HP O2 turned on, alarms on the HUD and Primary display will occur as soon as auto turn-on occurs through pressure or PO2 drop as above. Deaths have occurred because the diver has not been warned of the dangerous condition of HP O2 off. Compared with false turn-ons due to loop opening or flushing with diluent when at the surface or small shortfalls in battery efficiency, the auto turn-on is a major safety improvement. Breathing the loop, in all circumstances where the unit is breathable and PO2 cells operative, will cause a safe turn-on. These additional safety features should never be used for routine turn on. The unit should always be turned on by the user and pre-dive checks carried out as required in training and the operations manual. However, testing and confidence in this auto turn-on should be carried out occasionally under safe 0.70 bar or greater conditions. To do this, ensure the unit is off, flush with diluent until the PO2 falls and the LSS turns on. When a unit is activated by Auto turn on, the predive checks will depend on the period since last full predive checks were completed. If this is less than two hours, the shortened sequence will be required. This screen will remain on until the PO2 is restored by injection to the setpoint currently active. To turn the unit off, a long press of both switches is needed. To continue to the pre-dive setup screen, do a short press of either switch. Page 19 Vobster Marine Systems Ltd version: 1.5.2

21 Surface Status Screen The surface status screen indicates some detail on all systems at a glance. Further detail, gas configuration and system setup can be accessed from here. The main display utilises a colour OLED screen, information prioritising and uncluttered layout to ensure the general status and detailed support information is crystal clear to both diver and buddy if required. Display Screen and Menu Tree From the surface status screen, information and controls can be accessed along three menu branches 1) The status branch - a short push of both buttons enters a sequence of screen giving details on system status, resources levels, faults and alarm states. 2) The gas branch. A long left will enter a branch where setpoint can be selected along with automatic or manual control, plus diluent or bailout configuration or a switch to open circuit selected. 3) The control branch. In dive mode, a long Right push brings up the screen with details on diluent PO2 and the ability to move into the Dive Options (DVo) screens, from where information from sensors can be configured or omitted from the LSS. In surface mode, a short R push brings up the menu from which options including DVo can be selected. HUD The LSS can be routinely dived by using the Heads Up Display (HUD) as the main underwater human interface. This frees up the diver to concentrate on the mission or dive in hand. Page 20 Vobster Marine Systems Ltd version: 1.5.2

22 There are 3 warning levels indicated by Green, Blue and Red LED. 1) Solid Green - means there are no detected problems or active alarms. All enabled components are working correctly. Note: If a sensor has been disabled by the diver, this status is ignored by the system and the diver should compensate for the lack of this information with manual checking or self monitoring. 2) Green and Blue alternate flashing - warning is activated when a manageable error situation is in place. The correct response when diving is to check PO2 is breathable and take corrective action or ascend slowly on closed circuit monitoring the Primary or ISEC display as appropriate. A dive should not be begun with a Blue Green alarm active. 3) Flashing Red - warning is activated when a dive should be aborted on open circuit or not started. If diving, the diver should switch to the bailout gas and check handset for alarm information and breathable PO2 check. The HUD vibration alarm will also vibrate every ¼ second for 10 seconds, then repeat the 10 second alarm every minute. The LED states are configured for colour blind as well as highly stressed divers. The position of the LEDs coupled with the flashing or solid states, provide conditions that can not be confused with one another. Also, during stressful dive scenarios, the position and status is quick to comprehend and therefore the desired response is performed intuitively. The white LED indicates decompression status: White LED off = no decompression White LED flashing slowly = decompression required, diver is currently deeper than deco ceiling White LED solid = diver is at decompression stop White LED flashing fast = diver is shallower than decompression ceiling. Stop - if white LED remains flashing fast, descend until it is solid. White LED flashing fast = ascent rate greater then 10m/min. Stop - if white LED remains flashing fast, descend until is solid. If the HUD is set to PO2 mode then the green light also informs the user of the state of the PO2 in the unit: Green LED solid = within +/- 0.1 bar of setpoint. Green LED slow flash = PO2 above 0.4 but below 0.1 below / below setpoint. Green LED fast flash = PO2 greater than 0.1 above setpoint but less than 1.6 PO2. Red LED flash when PO2 more than 0.3 above / below setpoint, indicating loss of automatic O2 injection control. Red LED flash when PO2 below 0.3 and above 1.6 PO2. Normal dive states In normal dive states, both diver and buddy HUD will maintain a solid green LED. It is important to remember that this indicates that all systems currently enabled are working properly. If a sensor has been disabled by the diver, it s status is ignored - the diver must now implement a manual alternative. Example - HP sensor failure. The HP sensors are analogous to the fuel tank on a car. They indicate remaining resources of dive gas. In normal state, the LSS monitors the contents of the cylinder and also status of datalink data from the HP sensor. Breaking the connection between sensor and LSS could mean that either the sensor has malfunctioned or that the contents is zero. An alarm is initiated. The diver must now ascertain which of these conditions is true. The requirement to diagnose which failure state exists balances the simplicity of having crucial LSS resources monitored during normal no fault dive conditions. If a sensor data path is determined to be faulty, but resource such as HP O2 or DIL still accessible via automatic or manual injection, then the diver must determine whether this is a dive abort, dive turn or manageable error according to the dive and their individual risk appetite at that time. Page 21 Vobster Marine Systems Ltd version: 1.5.2

23 VMS recommends that the dive is turned and a safe ascent made on CC if loop is breathable and OC if the loop is or will become unbreathable. HUD/ Alarm states Red alarms take priority in the HUD over Green/Blue alarms. The HUD status is also duplicated with an icon in the top right corner of the Primary screen. With the LSS, a key task has been to process the fault levels and error conditions to indicate the status of the rebreather. In any event, the following alarm tables can be broken down into the following simple responses: Solid Green system ok to dive Green / Blue ascend safely or respond on closed circuit Red Flashing ascend safely or respond on bailout gas The status and summary screens provide the user with extra information on an alarm state or states to assist in taking the appropriate action. This information is in English, and all users should be adequately trained in interpreting this information appropriately. The table shows what status is shown for specific problems: PO2 States ALARM DESCRIPTION ACTION HUD STATUS PO2 OK Measured PO2 breathable and in setpoint limits GREEN PO2 OFF Rebreather control manually turned off Use open circuit bailout RED PO2 LOW PO2 breathable, but just outside setpoint control limits Check status and operation GREEN / BLUE PO2 HIGH PO2 breathable, but just outside setpoint control limits Check status and operation GREEN / BLUE PO2 VLOW PO2 dangerous do not breathe on LSS Use open circuit bailout RED PO2 VHIGH PO2 dangerous do not breathe on LSS Use open circuit bailout RED PO2 mlow PO2 breathable, but outside setpoint control limits Check status and operation GREEN / BLUE PO2 mhigh PO2 breathable, but outside setpoint control limits Check status and operation GREEN / BLUE PO2 > LOW PO2 breathable, but outside setpoint control limits due to setpoint change or doing ascent Check status and operation GREEN / BLUE PO2 <HIGH PO2 breathable, but outside setpoint control limits due to setpoint change or doing descent Check status and operation GREEN / BLUE PO2 CAL DO PO2 not valid calibration required of O2 cells Do not dive. Do O2 cell calibration before using LSS. RED Page 22 Vobster Marine Systems Ltd version: 1.5.2

24 ALARM DESCRIPTION ACTION HUD STATUS PO2 PRB DO Breathing loop not tested Prebreathe required Do not dive. Prebreathe loop before diving the LSS. RED GREEN / BLUE If doing PreDive PO2 SpInc Auto setpoint adjustment made Automatic setpoint adjustment just activated GREEN / BLUE *PO2 No COMMS PO2 not valid module not connected Do not dive. Check O2 TX module RED *PO2 Waiting for COMMS PO2 not valid waiting for communication from O2 module Do not dive. Wait for O2 TX module to communicate with main system. GREEN / BLUE Valve States ALARM DESCRIPTION ACTION HUD STATUS VALVE OK O2 solenoid injection valve firing OK GREEN VALVE FAIL O2 solenoid injection valve failed Use open circuit bailout GREEN / BLUE VALVE HiInj Valve over inject Valve injection not getting PO2 to setpoint. 2 minutes of valve firing triggers alarms. Check HP O2. Valve could be blocked GREEN / BLUE VALVE NoInj Valve not inject During diving this would occur if cells have a fault or the diver is manually adding O2 to the breathing loop. 5 minutes of no valve firing triggers alarm. Always expect the valve to fire every minute or more frequently. GREEN / BLUE Filter States ALARM DESCRIPTION ACTION HUD STATUS FILTER OK Filter duration status OK GREEN FILTER CHECK Backup filter O2 injection duration meter LOW Do not dive change filter GREEN / BLUE FILTER LOW FILTER EMPTY Filter CDM LOW Do not dive change filter GREEN / BLUE Filter CDM EMPTY Do not dive change filter RED FILTER NO COMM No communication with filter Check connector is plugged in correctly to canister. Check cable is not broken or damaged. GREEN / BLUE Page 23 Vobster Marine Systems Ltd version: 1.5.2

25 ALARM DESCRIPTION ACTION HUD STATUS FILTER BAD?? No temperature differential exists across the absorbent This could be due to inactivity during skills sessions. Abort if during a normal dive you see this. RED FILTER BAKCDM TPM switched off Complete dive using manual stack timer or O2 injection timer GREEN / BLUE CO2 > 5 mb CO2 levels high High CO2 levels. Reduce depth/workrate, consider open circuit bailout. RED Battery States ALARM DESCRIPTION ACTION HUD STATUS BAT OK Battery level OK GREEN BAT LOW Battery level LOW charge immediately Charge immediately system GREEN / BLUE HP Diluent States ALARM DESCRIPTION ACTION HUD STATUS OK HP level OK GREEN LOW HP below reserve level Turn on HP or fill cylinder GREEN / BLUE FAULT HP reading outside valid level Check HP sensor and cable for damage. Return for service. GREEN / BLUE RATE OK HP usage OK GREEN RATE HI HP usage high leak or not turned on Turn on HP. Check system for leaks. GREEN / BLUE HP O2 States ALARM DESCRIPTION ACTION HUD STATUS OK HP level OK GREEN *LOW HP below reserve level Turn on HP or fill cylinder bailout if diving *FAULT HP reading outside valid level Check HP sensor and cable for damage. Return for service. Bailout if diving GREEN / BLUE GREEN / BLUE RATE OK HP usage OK GREEN RATE HI HP usage high leak or not turned on Turn on HP. Check system for leaks. Bailout if diving RED Deco States Page 24 Vobster Marine Systems Ltd version: 1.5.2

26 ALARM DESCRIPTION ACTION HUD STATUS DECO STOP At correct decompression stop depth Stop at current depth to complete decompression SOLID WHITE DECO VDEEP Current depth much deeper than deco ceiling Ascend to decompression stop ceiling depth SLOW FLASH WHITE DECO CLOSE Current depth close to deco ceiling Ascend slowly to decompression stop ceiling depth SLOW FLASH WHITE DECO ALARM Current depth shallower than deco ceiling Descend to decompression stop ceiling FAST FLASH WHITE DECO NoDEC No decompression ceiling OFF ASCENT OK Ascent rate OK OFF ASCENT FAST Ascent rate too fast Slow down ascent rate FAST WHITE FLASH DEPTH LIMIT Depth too deep for LSS Ascend safely to depth within LSS range GREEN / BLUE Misc States ALARM DESCRIPTION ACTION HUD STATUS PREDIVE OK Pre dive checks completed OK GREEN PREDIVE ABORT Pre dive checks not completed as LSS went straight into dive mode Abort dive and perform Pre dive checks HUD warning not shown after 10mins of dive start GREEN / BLUE PREDIVE ABORT Pre dive checks aborted Perform Pre dive checks before diving HUD warning not shown after 10mins of dive start GREEN / BLUE SERVICE NOW LSS requires service. Servicing of the unit should take place every 200 dive hours, or every 24 months, whichever comes first. Either contact your local VMS dealer or return to VMS. GREEN / BLUE CELL CAL BAD Cell calibration attempted, but cell readings not valid Replace faulty cells. GREEN / BLUE FAILED PREDIVE Pre dive checks failed due to measured parameter not correct Perform Pre dive checks before diving GREEN / BLUE All of these alarms will cancel after 2 minutes of diving. This is to reduce risk of alarm blindness. 2 minutes is sufficient time for the diver to acknowledge and do something about the alarm. Page 25 Vobster Marine Systems Ltd version: 1.5.2

27 Co2 Systems Temperature Profile Monitor (TPM), Metabolic Rate Counter (MRC) and Timer. The CO2 filter duration and condition is critically important to CCR divers. Exhaustion or damage to absorbent material removes the ability to remove CO2 from breathing gas and forces an irreversible switch to OC bailout gas. Remaining duration is important to ensure that a safe return to the surface can be accomplished on the CCR. Damage must be detected as this can reduce or eliminate remaining capacity, for example through flood. There are three methods of assessing this duration and condition; heat from the chemical reaction (TPM), calculation of CO2 absorbed (MRC) and time compared to rigorous repeated tests. Temperature Profile Monitor (TPM) The TPM is a stick of eight thermistors running through the centre of the CO2 filter. The combined temperatures sensed by each thermistor give a profile of eight points that varies as the CO2 filter heats up with. This varying curve is known as the reaction wave. When a new filter is first used, only the top of the filter will show a heat peak from chemical activity. As use progresses, the mid levels activate and warm up, while the top cools and the base is not yet warm. Towards the end of use, only the base shows a heat peak. Divers should become familiar with these typical curves via the Status information branch. Using empirical data from many observations of filter use, an algorithm has been developed that allows a reasonable estimate of remaining filter duration to be determined. The algorithm is only able to give a reading of any reasonable accuracy when the unit is being breathed on. If the unit is not being breathed on, there is no relevant temperature profile because no current reaction is taking place and the current state of the filter can not be determined. Be aware that profiles will change due to ambient conditions and time since the filter was last breathed on. This is particularly relevant to the user during the pre-dive checks determining whether or not it is safe to use the filter for the next dive. The pre-breathe that is requested in the pre-dive checks is not sufficiently long to determine accurate usage readings. A general temperature profile is useful to determine basic operation of the filter: if the filter chemicals are working at all, if a filter is even present, and not flooded or damaged. But, a true reading of filter usage is not practical until around 10minutes into the dive. Therefore, to give the diver information prior to diving, a separate system is used. This is based on actual oxygen injection into the breathing loop and is know as the Metabolic Rate Counter (MRC). The TPM is not a universal indicator of filter state, due to the issues discussed above. However, it is a useful addition to the test and measurement sensors in the LSS, to help determine the condition of the filter and the LSS as a whole. Typical conditions highlighted by the TPM: 1. Smooth curve showing a varying temperature across the filter with a single peak usually implies a normal well working filter. 2. As the peak moves to the end of the filter (right hand side of the profile bar chart), the filter is being used up. When the peak is at the last two bars, change the filter as soon as possible. 3. A flat bar graph, or only a very small peak can indicate: a) a filter has been flooded b) the filter has not been breathed on recently. c) the filter has expired. d) there is a significant leak in the breathing loop causing water damage. e) No reading - the filter is not fitted! 4. Partial function. If the loop has been breathed on, and a curve is showing as in item 1 above, there could still be a gas bypass in the filter. The filter will show a reaction curve, but some gas can be bypassing - not all the gas, but some. This small amount of bypassed gas can still be sufficient to cause CO2 toxicity. Therefore the pre-breathe must still be performed diligently, to ensure no CO2 toxicity symptoms occur. If CO2 toxicity symptoms do occur, stop breathing on the loop immediately, and seek medical attention. Page 26 Vobster Marine Systems Ltd version: 1.5.2

28 NOTE 1. Even an expired filter that will not scrub sufficient CO2 out of the exhaled gas will still perform some CO2 absorption, and therefore still have some temperature profile. So do not use the filter profile alone to determine the safety of the breathing loop. NOTE 2. Due to basic physics of heat flow and gas flow through the filter, the middle to end of the filter will often show the peak of the temperature profile. This means it is harder to determine the difference between a 50% remaining to 25% remaining filter than a 99% to 75% remaining filter. So always be conservative, and change the filter sooner rather than later. Do not risk any life threatening situations for the sake of a few extra minutes on the filter, or the cost of this small amount of absorbent. NOTE 3. In high ambient temperatures, it may be hard to activate the absorbent to the required 30 degrees above ambient Metabolic Rate Counter (MRC) Co2 creation is directly proportional to O2 consumption by the diver, allowing the overall life of the filter to be determined from how much O2 has been injected into the breathing loop for that filter. It is extremely useful when unforeseen conditions, such as tide, stress or workload cause CO2 production greater than anticipated by the timer and previous testing. In these circumstances remaining duration is reduced and the diver needs to be aware of this. The MRC will decrease the remaining filter life to match CO2 production by the diver (and therefore absorption by the filter) indicated by the O2 injected into the loop. However, this requires that the user tell the system when a new filter has been inserted. It is also open to abuse, as the user can falsely tell the system that a new filter has been inserted, leading to overestimation of actual remaining filter capacity. Therefore, the two systems of the TPM, and the O2 injection monitor should be used together to determine the filter life remaining. Timer Thirdly, there is an overall timer that just relies on time since the last filter change notified to the system by the user. This also is open to abuse for the same reasons as the O2 injection monitor above. It however, uses no input of O2 injection, therefore will prompt a filter warning simply when the filter has been used for over 5 hours. No matter how many safety monitoring systems are in place, use your own common sense and discipline to ensure you do not push the life support systems beyond their designed limitations. It is your life being supported - respect the equipment and its limitations. Page 27 Vobster Marine Systems Ltd version: 1.5.2

29 PO2 module The PO2 module contains three electrochemical cells which each independently monitor the PO2 of the gas they are exposed to. PO2 data is fed from each cell to dive management computers via two independent circuits. Route 1 sends the data to the primary computer for processing via voting logic, sampling and averaging algorithms, the results being presented to the diver as a single PO2 figure on the primary handset. Route 2 sends the data independently to the ISEC, where all three cell readings are displayed and an averaged level used for decompression calculation. The PO2 module transmits it s data via Infra Red link to the electronics pod, avoiding potentially troublesome wired links from pod to module and allowing separation of unit for travel. It has it s own rechargeable power supply from two lithium ion batteries. It is recharged independently from the electronics pod. NOTE: Cells must be changed 18 months from manufacture date to give stable, accurate readings. Unstable or inaccurate readings complicate PO2 analysis and O2 injection. Page 28 Vobster Marine Systems Ltd version: 1.5.2

30 CO2 Sensor Page 29 Vobster Marine Systems Ltd version: 1.5.2

31 The CO2 sensor uses infra red sensing to detect levels of CO2 post filtration, providing an additional level of direct CO2 measurement to the suit of indirect measurements from TPM, O2 injection monitor and timer. This completes the most comprehensive suite of CO2 and filtration performance monitoring available to the sport diver. The CO2 sensor must be calibrated at least each month and the analysis gas dried before CO2 measurement. this is due to the potential confusion between water and CO2 molecules. The high operating temperature of the units stack is crucial to minimising condensation, with final drying being provided by an absorbing sponge contained in the cap covering the sensor. This sponge should be changed each diving day, or when wet. isec functions The Independent Secondary handset has two functions. It is turned on with a long push of the Right button. 1) At a glance status of each cell. this information should be accessed every five minutes, or at OC / CC gas switch to validate displayed Primary PO2. 2) Decompression and dive management information based on in loop PO2, but with no control of O2 injection solenoid. 3) O2 Cell status monitoring. The handset displays the three O2 cell readings as a default state. This information is derived direct from the backup circuit of the PO2 module and remains active in the event of main circuit boards flooding in the head, or primary screen failure. This information is a fully redundant method of PO2 monitoring, both to validate Primary displayed PO2 and to provide an viable alternative to enable dive abort on closed circuit. The three PO2 readings can be switched to mv readings with a single short push of the lower (Left) button. The mv readings indicate activity of cells and are an important indicator of the two cell error situation. 4) Decompression and dive management information: The PO2 information above is actually displayed as a screensaver option to the dive management screen of the ISEC. The dive management screen can be accessed using a short push of the Right buttons, but will revert to the PO2 information after a time interval preset in the setup menu of the ISEC. In surface mode the ISEC offers access to a number of setup and dive parameter screens in a continuous wheel accessed by short pushes of either left or right buttons. These screens include Page 30 Vobster Marine Systems Ltd version: 1.5.2

32 PO2 cell calibration Closed and Open circuit gas configuration. Time and date setup Dive log information Dive planning and simulate modes In dive mode, the screen displays time and depth options, along with user selectable information such as time to surface. In this mode, a long left push access breathing gas information, including switching to open circuit. Long right access decompression information based on currently selected active gasses and OC or CC mode selected. The decompression information is derived from the PO2 measured in loop and converted into FN2 and FHe based on inert gas ratios of currently selected diluent. The three PO2 readings remain in the top right corner of the screen during operation in dive computer mode. The ISEC has a fully independent power source for backup situations. Under normal conditions it draws power from the Primary batteries, switching to it s own independent source when Primary power falls below 30% NOTE: Configuration of the ISEC is independent of the Primary handset. Diluent and OC bailout gasses, stepping and dive options must be programmed separately on both handsets. Diluent or OC bailout switches must also be made separately on each handset. NOTE: The ISEC does not include LSS resource monitoring of the CO2 filter or HP gas levels. As such, should the diver find themselves with only an ISEC for dive control they must be in a scenario that permits them to substitute LSS monitoring of these resources with their own self monitoring of symptoms of hypercapnia. Page 31 Vobster Marine Systems Ltd version: 1.5.2

33 Section 3: Physical anatomy Design Criteria The mechanical system has been designed with several key features in mind. Reliability Breathing performance and pathways Maintenance Simplicity and flexibility of operation (particularly in multi-task situations) 1) Reliability: As the unit provides a breathing system for the user in a non-air environment it is vital it does this reliably, and in a manner that is tolerant of system faults should they occur while diving. This is achieved by: a. The fundamental philosophy of having a mechanical system, which can work in conjunction with or separately from the electronics, allowing the diver to control gas input even if there is a complete main electronics system failure. b. Use of electronics implemented, tested, evaluated and developed through numerous previous versions. The VMS RED SERIES is created from the best of what is proven to work in CCR LSS technology. 2) Breathing Performance and Pathways: This is a very clear-cut area and is laid down in a CE standard. The unit has already undergone testing in accordance with EN14143:2013. This testing not only covers breathing parameters, dive duration and oxygen control but also includes the field of user interaction and robustness. At this stage the unit operates in excess of many requirements laid down by CE. All components of the breathing loop are designed to give maximum gas flow while providing total robustness. All gas handling lines are rated at 10 times their usage pressure and where required oxygen cleaning standards are adhered to. The unit has independent Oxygen and Diluent (make-up gas) pathways. O2 is injected via a solenoid before the CO2 filter, while Diluent is injected into the analysis chamber. The advantage of this staged gas modification is to ensure O2 is fully mixed before analysis, while the function of the diluent as a solution for both hypoxia and hyperoxia. 3) Maintenance: All parts are designed to be simply, yet robustly attached allowing simple disassembly for cleaning and maintenance. 4) Simplicity and flexibility of use: All controls are positioned to support the idea of the triangle of access familiar to technical divers, with life support controls in or on the triangle. The concept of a minimally cluttered harness is supported by the back mounted counterlung. Where possible controls are also operable with either hand. Consideration has also been given to cold water operation in thick wet gloves, dry gloves or even possibly in three fingered mitts. Page 32 Vobster Marine Systems Ltd version: 1.5.2

34 The Breathing Loop The breathing hose ends are fitted with a bayonet type connect / disconnect which is inserted into the head of the unit and secured by a locking spring and a ¼ turn locking ring as a secondary lock. At the mouthpiece end, the hose ends are held in place by two white plastic C clips. The hose end can be rotated for adjustment and comfort. It is important to ensure these clips are in place as part of your pre dive checks. Incorrect assembly is prevented by differing bayonet end lengths and colour coding. Green is exhale and runs on the divers Right, while Red is inhale on the divers Left. The differing bayonet lengths for breathing hose to body attachment prevent fitting of cover when hoses are incorrectly fitted. Units with a BOV (Bail out Valve) The BOV can only be attached one way round. Reversal prevents attachment of the LP hose, which also prevents completion of PreDive checks. 1. HUD 2. Gas flow direction indicators 3. BOV C clips 4. Exhale Hose 5. Inhale Hose 6. Dive selection switch 7. Flow Stop 8. Second Stage regulator Note: The flow direction arrows should be pointing at the HUD, the Dive Selection Switch should be pointing away from the unit and the second stage should be pointing down if the mouthpiece is correctly fitted. Page 33 Vobster Marine Systems Ltd version: 1.5.2

35 Units with DSV (Diver Selection Valve) DSV in the Open (CC) position. This is the normal breathing position of the unit. DSV in the Closed position. This is used to seal the unit if you wish to remove the mouthpiece under water. Always ensure the white retaining clips are fully engaged before diving. Note: The flow direction arrows should be pointing from right to left when looking at the front of the unit. Page 34 Vobster Marine Systems Ltd version: 1.5.2

36 1. Exhale hose end with cupped collar. 2. Inhales hose end with rounded collar. 3. Note colour coding of hose and hose port release button. 4. Insert hose into hose port and push firmly, listing for a firm click. 5. Hose end locked in. if fitted correctly you can not pull it out. 6. Locking cover gives extra security with half turn clockwise twist. Inhale port is fitted after Exhale port, and removed first. The locking process is the same as the Exhale port. Note: For ease of fitting you can depress the release button while inserting the hose as the spring is quite stiff. Page 35 Vobster Marine Systems Ltd version: 1.5.2

37 The Mouthpiece and Hoses The VMS RED SERIES ships with either a Bail-out Valve (BOV), or Diver Selection valve (DSV). The BOV attaches to the in-board diluent circuit. The BOV is designed as the primary bail-out (providing a sufficient/planned volume is carried) and as the sanity breath valve at all other times. A switch to off-board open circuit gas should then be performed as soon as possible. The switch between OC and CC is controlled via a selector barrel operated with either hand on the front of the BOV. Selection should be EITHER OC or CC - a halfway selection can cause breathing loop problems and a pathway for water ingress. In closed circuit mode, gas flow is regulated in one direction by one way silicone valves. Inhalation is from the Left hose, with exhalation to the right hose. Warning: If an in-line shut-off is used in the LP feed to the BOV this should be open at all times especially on descent. Opening the shut-off in-water after a closed valve decent may cause an excessive flow of gas and may damage the second stage diaphragm. Note: When the mouthpiece switch is in the horizontal position it is operating in closed circuit mode. In the vertical position it is in open circuit mode and the loop is closed. Page 36 Vobster Marine Systems Ltd version: 1.5.2

38 If fitted with DSV you can simply switch the mouthpiece between CC and closed. In the closed position you cannot breath the unit. This position is used to prevent water ingress into the unit if the mouthpiece is not in your mouth. There is a small hole on the bottom of the mouthpiece, it is important to not that as you switch from Closed to CC that you need to clear any residual water in the mouthpiece before inhaling. This is achieved by blowing into the mouthpiece in the closed position until you see bubbles come out of the bottom of the mouthpiece. At this point it is safe to switch the mouthpiece to CC. The picture above shows the DSV in the correct orientation and in the Open (Closed Circuit) Mode Mouthpiece Retaining Strap Your unit comes as standard with a Mouthpiece Retaining Strap, this is primarily for safety as it prevents the mouthpiece coming out of your mouth should you become unconscious, however it also reduces jaw fatigue on long duration dives, or if you are also using a Scooter/DSV. Page 37 Vobster Marine Systems Ltd version: 1.5.2

39 The above image shows the attachment of the Strap to the breathing hoses, by looping the tworubber O-rings (indicated by the arrows) over the end of the hoses before attaching the mouthpiece. When preparing for diving. Loop the strap over your head and adjust so that it is holding the mouthpiece in your mouth, but so tight as to cause discomfort. Above you can see the strap correctly adjusted. IMPORTANT! If you should need to bail out onto open circuit, firstly CLOSE THE LOOP, then remove the mouthpiece from your mouth and drop below your chin. You should practice removal and replacement of the mouthpiece regularly to ensure you are familiar with the procedure and able to respond correctly in an emergency. Head, flowcone, filter and body The rebreather consists of three housings with the top housing containing three subsidiary assemblies. The head housing at the top of the body containing PO2 module, electronics pod and CO2 module. It also has inlets for O2 and diluent. Diluent can enter from either ADV or manual hoses. The removable electronics pod containing primary electronics. This has plug and play attachments for Primary and ISEC handsets, Primary and buddy HUD, CO2 monitor and bifurcated digital HP sensor lead. The electronics pod connects with PO2 module and TPM via infrared link. Recharging of both primary and ISEC batteries are charged through banana plug ports in this housing. The PO2 module is housed in the top of the head housing. It is independently rechargeable. The CO2 module is also housed in the top of the head housing The flow cone fits into the head housing and incorporates the primary CO2 seal for the absorbent canister. It is vital that the seal is kept clean and greased. It should be inspected after every canister change. The seal should be replaced yearly or every 100 hours which ever is the sooner or if any damage is suspected. HP sensors, Primary HUD, Buddy HUD, Primary / ISEC handsets and CO2 monitor are all connected to the electronics pod by Plug and play cables. The middle housing (tube) that holds the canister. This also provides attachment by velcro straps to the backplate and fixings for cylinders. The canister base that includes the Filter carrier, TPM and canister spring system Over Pressure Valve (OPV) / water dump. Page 38 Vobster Marine Systems Ltd version: 1.5.2

40 The head housing and canister base attach to the centre housing by ¼ turn lock system secured by a spring loaded securing pin at each end. Analysis chamber After passing through the filter, gas flows up around the outside of the filter. It is prevented from entering the flow cone between the flow cone and the filter by the triple CO2 seal. Instead it enters a space between inside the head housing and around the flow cone which the CO2 and O2 sensors project into. Gas analysis for CO2 and O2 takes place at this point, where gas is fully mixed and therefore providing accurate information on the gas to be inhaled in the next breath. The downward pointing position of these sensors is also important to minimise the effect of moisture on analysis and therefore contribute toward both gas stability and the minimisation of false alarms. Counterlung The LSS comes complete with a single back-mounted counterlung (BMCL). This is attached via a quickdisconnect system with secondary security catch to the canister head to allow easy cleaning. To remove the counter lung loosen the upper velcro band, undo the rubber catch, depress the spring loaded release button and pull the counterlung out by the fitting. Before refitting the counterlung, check and clean the O rings as required. Present the counterlung collar carefully to the spigot to prevent damage to O rings. Refit the rubber catch and tighten the velcro band to ensure canister is firmly attached to the backplate. Gas Block Automatic and Manual operation. Gas injection routes are similar in pattern for both O2 and diluent gasses. Both feature a supply of gas from HP cylinders via first stage pressure reduction to LP hoses that supply gas blocks on the front of the rebreather. These gas blocks route gas by default to the solenoid in the case of O2 and the ADV in the case of diluent. Alternate routing of the gas direct to the loop is achieved by operation of the manual addition buttons. This alternate routing is for use in the case of solenoid or adv failure, either open or shut. In the case of diluent, gas will now flow via unrestricted LP scuba hose to the corrugated inhale hose. In the case of O2, gas flow joins the small bore pipework downstream of the solenoid flowing to the same moulded orifice used for automatic gas injection. This restricted route provides a safety feature that physically slows the rate of O2 injection from either solenoid malfunction open or manual addition being inadvertently operated. Although correct O2 sensor operation and alarm structure will warn of elevating PO2, this feature ensures that prompt response to the initial blue green alarm should keep PO2 inside breathable limits unless rapidly descending or ascending. The gas blocks also have the option to isolate the solenoid or ADV respectively via flow stop valves. Off board gas can also be hot swapped to the blocks via Omniswivel off board connectors. Page 39 Vobster Marine Systems Ltd version: 1.5.2

41 1) Isolation slider open. 2) Isolation slider close. 3) O2 Manual addition. 4) DIL manual addition. ADV housing The ADV housing contains a simple KISS valve that opens due to a pressure differential between the inside of the rebreather (lower) and external ambient (higher). This pressure differential pushes the membrane in, activating the valve via a lever, allowing diluent to flow into the analysis chamber. Solenoid The solenoid is activated via electromagnetic coil moving a steel piston. The coil is activated from the main computer in response to PO2 being detected below setpoint. The activation system for the solenoid has been carefully designed to prevent single electronic component failure causing the solenoid to fail open. Page 40 Vobster Marine Systems Ltd version: 1.5.2

42 1) Solenoid. 2) O2 Injection hose. 3) Solenoid O2 feed. 4)ManualO2 Inject feed. Plug and play cables Modular cables balance the risk of water ingress to crucial electronic spaces from damaged cables, with the superior data transfer of wired links. The cables fitted to the unit contain eleven cores and each cable terminates in a moulded rubber plug containing eleven female connectors, one per core. Each female connector is sealed with an individual O ring to prevent water ingress from cable damage passing through the pin connectors to the interior of the electronics pod. The plug itself is sealed from the environment by two O rings and correct connection ensured by a moulded index pin. The plug locates into a chrome plated bulkhead on the electronics pod which is also potted on the inside to further ensure water tight performance and critical circuit protection. These cables should be regularly checked for damage to the sheath. The connectors should be kept clean and free of dirt or hairs, with a light coat of silicone (not Tribolube) grease. If corrosion is observed on the pins, they can be cleaned using contact cleaner or IPA. Do not over clean these contacts. The cables can be removed by unscrewing the nut and sliding it back up the cable. Gently pull the cable from the socket. Refitting is by visually locating the index pin, lining up the index groove on the plug and carefully inserting the plug into the socket. Screw up the retaining nut. Do not force the plug into the socket by tightening the nut. Do not twist the cable to find the index pin and groove alignment. Page 41 Vobster Marine Systems Ltd version: 1.5.2

43 1) Plug n Play cable end, note locating groove. 2) Plug n Play socket, note locating notch Page 42 Vobster Marine Systems Ltd version: 1.5.2

44 Harness and BCD As per CE requirements, the unit ships with a Wing style BCD which can also fit a 280mm (11 ) mounting and an adjustable harness. The BCD used is either the Scubatech Techline Donut 22 Special Edition Rebreather wing or Techline Peanut 21 wing, see separate user manuals or visit: There is also a summary of the user instructions sewn inside the outer cover of the wing. You can access this by unzipping the outer cover. Cylinders Our units ship with 2 litre diluent and O2 cylinders. The Diluent cylinder has an M25 attachment, while the Oxygen has an M26. This prevents accidental connection of the cylinders to the wrong regulator. Over pressure valve The VMS RED SERIES uses a combined water release and balanced over-pressure release valve. The balanced valve ensures that (when the release pressure is set on the surface), the underwater release pressure is near-constant in any orientation. When the unit vents it also removes any water from the system. This function can also be performed manually by over inflating the system. 1. Remove OPV Hose 2. Unscrew OPV cover, you can use the threaded insert to give extra leverage. 3. Remove OPV cover 4. OPV exposed for adjustment Note: replacement is the reverse of the removal process. It is important that the OPV hose is connected, and routed up the back of the unit so that the top of the hoe is close to the couterlung. Page 43 Vobster Marine Systems Ltd version: 1.5.2

45 Section 4: Rebreather function while diving Normal dive function, no error states. Once assembled and the pre breathe sequence has validated this assembly, the unit will maintain a PO2 of 0.4 at the surface. This represents a mix of air or trimix diluent and O2, which also provides to confirmation of continued solenoid. Any metabolic activity by the diver at the surface will cause a drop in PO2, triggering the solenoid to open and an injection of O2 replaces the metabolised Oxygen. When descent is begun, the counterlung will collapse according to Boyles law and the ADV opens on the next inhale, as ambient pressure pushes in the membrane. This allows diluent into the loop, dropping the PO2. The cells register this drop and trigger the solenoid to fire, allowing O2 into the loop and raising the PO2 back to setpoint. Once the PO2 is back to 0.4 the loop will have a breathable volume. At a depth of 2.5 m, the setpoint is increased to 0.7 Bar, requiring the injection of some additional O2. The increased volume in the loop from this injection may require some venting from the nose to regain neutral buoyancy. As the diver descends further this cycle will be repeated until target depth is achieved and the PO2 can stabilise at the value determined during dive planning and unit programming. If the unit is being dived in MANUAL setpoint mode, the setpoint will be the value set throughout the dive - in the example above, this is 0.7 Bar PO2, but could equally be 1.2 or 1.3 Bar. If this is the case, the unit will attempt to create this PO2 in the loop from 2.5 m depth downward, requiring significantly more O2 to be injected in the shallows and more venting as a result. An alternative is AUTO setpoint mode, where the setpoint values programmed in DIVE OPTIONS (DVo) are only activated once 20m is passed. The unit will transition the setpoint from the 0.7 Bar setpoint initiated at 2.5m depth, to the full value incrementally from 12m depth, achieving full setpoint value at 20 m. During this transition, the Blue Green alarm SPINC will be displayed. At target dive depth O2 will be injected to match the drop in PO2 caused by metabolic activity (proportional to physical exertion) by the diver. The higher the level of activity, the more injection required. CO2 produced by this activity will be totaled by the Oxygen injection meter and the filter remaining value adjusted. On ascent, the PO2 will drop below setpoint according to Daltons law and injection of O2 triggered. This ascent presents the diver with an increase counterlung volume according to both Boyles law and this additional Daltons Law injection. To prevent this additional volume causing both buoyancy and gas efficiency problems, some excess must be again vented though the nose to achieve minimum loop. The advantage of CCR during ascent is that its maintain setpoint, increasing the FO2 of the loop as pressure (depth) decreases, increasing decompression efficiency from the beginning of ascent. O2 HP failure HP O2 or HP O2 RATE alarms indicate problems with the Oxygen resource or inaccurate reporting of the resource by the sensor. If the pressure in the cylinder is dropping faster than normal, then a Blue Green HP O2 RATE alarm will be triggered. The diver should check for Oxygen loss and control the problem. If the O2 RATE alarm is ignored, then a RED HP O2 alarm will be triggered at 30 Bar pressure remaining. The diver should confirm if Oxygen is available with the Hypoxia drill. If there is no remaining O2, the unit can no longer function as a CCR LSS by injecting O2. The only source of rebreathable O2 available to the diver in this situation is the Diluent. However, this is far less efficient and running a long ascent in SCR mode consumes more gas than the onboard Diluent cylinder contains. In this situation, off board DIL can be used, with both onboard HP sensors disabled. If Hypoxia drill confirms that O2 is still available, but pressure reads zero, then the sensor has been diagnosed as faulty. It can be turned off in DVo and the Blue Green alarm is cancelled. This is an example of the value of the SOLID GREEN status - everything remaining is functioning well. The response to turn off the sensor is required to prevent alarm blindness to other Blue Green alarm states. VMS recommends that once the HP O2 sensor isolated and cylinder contents remaining is unknown, the dive should be turned and a safe ascent made to the surface in CC mode. Page 44 Vobster Marine Systems Ltd version: 1.5.2

46 DIL HP failure HP DIL or HP DIL RATE indicate problems with the Diluent resource or inaccurate reporting of the resource by the sensor. If the pressure in the cylinder is dropping faster than normal, then a Blue Green HP DIL RATE alarm will be triggered. The diver should check for diluent loss and control the problem. If the DIL RATE alarm is ignored, then a Blue Green HP DIL alarm will be triggered at 30Bar pressure remaining. The diver should respond as trained, remembering that injection of Diluent is not required on ascent as the loop will expand according to Boyles law. This means that OC Bailout is not the only option for a safe ascent. Once the problem is diagnosed and controlled, the alarm should be cancelled by turning off the HP sensor in DVo menu to avoid alarm blindness to any subsequent problems, or the primary switched to OC mode if OC Bailout is required. A fault in the HP sensor or breaking of the HP cable, could mean that either a very false high pressure is reported, a false low pressure, or most likely no pressure at all in the case of broken comms. The change between normal pressure and low pressure would trigger an HP DIL RATE alarm. A change to no pressure will trigger a HP DIL alarm. In either case, the alarm can be verified by the diver, with a short injection of DIL - if DIL can be injected then, the zero pressure is false and the sensor should be isolated in DVo and an ascent made in CC mode. Alternatively, off board DIL could be connected and the gauge on the off board cylinder used to manually manage the dive. If the diver chooses to ascend on CC with no information on DIL levels, they should take great care not to require an injection of DIL which may not be available, for example through bouncing on stops or irregular ascent profile. Solenoid failure Failsafe of oxygen addition valve This section provides a detailed description of the ways in which the solenoid valve operation has been considered in various failure modes The oxygen addition valve has two main failure types: Valve stays permanently shut Valve stays permanently open These scenarios are discussed below: Valve stays permanently shut: From a diver safety point of view, a permanently shut valve causes a gradual decrease in oxygen level that is warned of in the display systems. This failure scenario can happen due to an electronics failure, or a mechanical failure of the valve. This failure mode is gradual, initially causing a BLUE GREEN PO2 mlow alarm and a diver has time to sort out this by using the manual addition valve to compensate for solenoid failing shut. Failure to compensate will result in a further fall in PO2 until the RED PO2 VLOW alarm compels OC bailout. The manual valve has no connection to the electronics micro-controller control system, so is isolated from any impacts of electronics failure and a fully redundant diver operated alternative. Valve stays permanently open: This failure scenario can cause a rapid increase in the partial pressure of oxygen level, which can quickly incapacitate and ultimately kill the diver. This failure type could be caused by a mechanical or electronics failure. Due to the rapid nature of the onset of diver problems from this failure type special attention has been given to reduce the risk of this type of failure from an electronics and mechanical standpoint. The following gives the potential scenarios and methods for reducing the probability of failure: Valve stuck open due to debris under the valve mechanism. This has been guarded against by the installation of a filter in the O2 addition line. However, should this still happen, the diver can shut off gas using the main cylinder shut off see below. Software and Electronics drive circuit failure causing solenoid failure. The drive circuit contains a electronic hardware failsafe that guards against electronic failure open, independent of controlling software. Page 45 Vobster Marine Systems Ltd version: 1.5.2

47 In the event of either of the above failures happening, despite the system precautions, the diver can shut down the oxygen supply by turning off the oxygen supply at the main cylinder. Alarms on the HUD, Rear facing O2 display and Main display will show high Partial pressure O2 warnings, and the backlights will flash. The piping system has been designed with a minimum of reservoir, so that turning off the cylinder O2 supply will quickly stabilise the O2 level. The diver can then add diluent to bring the O2 back down to safe limits via the Hyperoxia drill. ADV failure Possible failure modes of the ADV are failing open, or failing shut. The operational status of the ADV is not monitored directly by the unit, but the effects of ADV failure on PO2 will cause alarm states to activate as PO2 drops. Failing open will allow Diluent to flow into the loop, causing breathing feel to change and cause discomfort plus positive buoyancy problems. This is also known as an internal Boom scenario. Appropriate action is to close the isolation slider above the diluent gas block. Once loop volume has been controlled, addition of diluent can not be made via the redundant backup method of manual addition via independent hose routing. Failing shut will be detected via significant breathing discomfort as loop volume drops, for example during descent. Immediate manual diluent injection is required to restore breathable volume and a check made to ensure that ADV isolation slider has not been accidentally closed. Further manual diluent injection will be required for further descent. Diluent injection is not required on ascent as breathing loop gas expansion maintains breathing volume. Gas leaks HP O2 or DIL gas leaks will cause a drop in cylinder pressure, exaggerated by the small cylinder size. As such early detection of gas leaks is critical in SCUBA CCR systems. The rate of this drop is monitored by the LSS via the remaining HP reading. An excessive drop in DIL pressure triggers a BLUE GREEN HP DIL RATE alarm, followed by a BLUE GREEN HP DIL alarm when the pressure drops below the reserve level of 30 Bar. An excessive drop in O2 pressure triggers a RED HP O2 RATE alarm, followed by a RED HP O2 alarm when the pressure drops below the reserve level of 30 Bar. The procedure for all RED alarms is to bailout to OC on the BOV and check handset for PO2 and alarm status. In this case, once the initial glance has confirmed that the loop has remained breathable, a switch can be made back to CC mode during problem solving. Leak diagnosis and troubleshooting may require the assistance of a buddy or mirror. If the problem is resolved any decision to continue with the dive must be made with regard to sufficient gas supplies remaining. Loss of gas through an external leak may have caused warning bubbles, but the value of the LSS is that it the diver need not rely on hearing bubbles that could be masked by environmental noise (for example, OC divers). Detection of rate of gasdil or O2 pressure drop by the LSS BEFORE gas pressure hits critical levels, prevents considerable problems such as relying on OC Bailout or SCR ascent. Both are feasible, but any dive is better if they are avoided through early warning and distraction of the diver is removed from this process. Absorbent failure CO2 absorbent failure creates critical and potentially fatal levels of CO2, compounded by the vagueness of physiological symptoms and the rapidity of symptom escalation to unconsciousness and drowning. Absorbent failure can occur through: 1) Exhaustion - the chemical capacity to absorb CO2 has been exceeded. Co2 now passes unfiltered through to the diver. 2) Over breathing - passing gas too rapidly through the absorbent does not allow sufficient dwell time for the CO2 to be absorbed. 3) Excessive CO2 production - too much CO2 is produced by the diver for the material to remove all CO2 contained in a single exhalation. 4) Impairment of material - the filter function can be compromised through water ingress. Safe function of the CO2 filter also relies critically on Page 46 Vobster Marine Systems Ltd version: 1.5.2

48 1) Correct packing of the absorbent material to prevent channeling, or loosening of the absorbent allowing gas to pass through unfiltered. 2) Diver fitness and breathing technique. Although beyond the scope of this manual, filter safety margins, duration and function can be improved by increasing VO2 max and maintaining a controlled breathing rate through exertion. It is important to note that monitoring by the LSS is of conditions in the loop, not CO2 levels in the diver. Poor breathing habits can cause CO2 retention in the diver which is not detectable by the LSS, but which can impair decision making and health. LSS warning of CO2 absorbent failure occurs through the following pathways and related alarms. Sensors and LSS components supplying information for these alarm states are the TPM measuring filter produced heat (or lack of it), gaseous CO2 monitor and Oxygen Injection rate meter. 1) Chemical exhaustion. There are two consequences to a loss of chemical activity. Firstly, the heat generated will fall, detected by the TPM and triggering a FILTER??? alarm. The diver should monitor themselves for signs of hypercapnia, monitor the handset for CO2 levels and ascend on the loop. Secondly, CO2 will begin to pass through loop and be detected by the CO2 monitor. This will be displayed in the lower R of the screen as a numerical value. When this crosses the 5mB threshold it will trigger a RED CO2 HIGH alarm and the switch should be made to OC Bailout. 2) Over breathing. High levels of exertion will cause CO2 to be passed through the filter and detected by the CO2 sensor, despite TPM registering healthy levels of absorbent activity. However, it is important to note that the breathing rates required by the CE testing to EN14143:2013 for CO2 absorption reach 75 l/min. This is a very high rate for a human to achieve and passing at this rate is an indication of the high performance of the filter in these circumstances. 3) Excessive CO2 production. CE test are run at 1.6 l/min of CO2 production, with a breathing rate of 40 l/min at a temperature of 4 C. At this level, no CO2 is detected by the sensor until absorbent is exhausted, again indicating reliable filter design. Outside this range the CO2 sensor provides direct measurement and warning of increasing CO2 levels in inspired gas. Excessive CO2 production will also require excessive O2 injection, which will cause the O2 injection meter to downgrade filter life expectancy accordingly. This will result in a premature BLUE GREEN FILTER LOW alarm, but still with sufficient time to cease poor breathing and make a safe ascent until either the surface is reached or RED FILTER EMPTY requiring a switch to OC Bailout. 4) Impairment of material. Despite the good flood recovery performance of the unist filter, excessive water causes a drop in temperature, triggering a TPM alarm. The TPM graph can be checked via the STATUS screen branch and cautious diagnosis made. Mild impairment may not result in CO2 breakthrough, but small floods close to the end of filter life may reduce remaining chemical activity below effective levels, causing rising CO2 levels and eventually CO2 HIGH alarm. O2 Sensor failure Sources of incorrect O2 readings The units PO2 module is an O2 analyser with three cells and two independent reporting routes. However, normal rules of O2 analysis apply to the exercise of determining PO2. To recap: - Sensors must be less than 18 months since date of manufacture. - Sensors must be correctly calibrated as described earlier. - Sensors must not be wet. The VMS RED SERIES benefits from a higher filter temperature and better insulation than other CCR units, which helps create a better environment for analysis with less condensation. Any condensation on the cell surface would create a false reading. The reading would probably be low due to the condensation limiting the area available for analysis and hence a lower amount of electrical activity being detected, leading to a false low reading. - Sensors must not be damaged. - Electrical connections to sensors must be robust and secure. The units cells do not use thin wire connectors, instead using a moisture resistant and robust 3.5mm jack connector. These connectors are easily inspected and cleaned. Page 47 Vobster Marine Systems Ltd version: 1.5.2

49 Multiple Sensor failure These two alarms assist the diver in detecting conditions where all three sensors are reading either high or low together and within range of each other. Rogue sensors are dealt with below. VALVE OVER INJ If the valve is injecting for over 2 minutes without the PO2 getting to within 0.1 of the setpoint, then a Valve Over Inject alarm will occur (Valve Over Inj). This feature also has the effect of warning the user during diving if the cell readings remain below setpoint for too long. This could be caused by solenoid being fired, but failing shut as above, undetected loss of HP O2, or cells not reading the PO2 correctly. In the last case, actual loop PO2 is higher than indicated by an unknown, possibly toxic amount. This requires investigation by the diver. VALVE FAIL If the PO2 remains higher than 0.1 above setpoint for over 5 minutes, then a Valve Not Fired (VALVE FAIL) alarm is created, warning the diver that a solenoid firing has not been needed for this time. In this scenario, the valve has not been triggered because the sensors are reading a false high, possibly masking a lower PO2 than setpoint and hence higher levels of inert gas. Decompression calculations are now less accurate by an unknown amount and the loop may be becoming hypoxic. This helps ensure the system does not have bad sensors. During diving, the O2 injection valve should always have fired within a 5 minute period unless manual O2 injection has been performed, which the diver would be aware of doing. When at the surface, to force injection, breathe on the LSS to drop the PO2 below setpoint and cause an injection. This will reset the alarm counter. This alarm helps detect a severe PO2 cell failure where cells fail with a high reading. When not diving, if the valve is injecting for over 8 mins without the PO2 reaching within 0.1 of setpoint, then the turn off timer will start to count down. Normally, the count down timer is reset after each valve fire, but after this 8 minute period of no effect on the PO2 to achieve setpoint, the turn off timer is reenabled. If cells are suspected of malfunction either high or low, the DIL Flush Cell Check procedure can be followed, with confirmation of mv readings to determine cell function. Rogue sensors Single sensor errors are easier for the unit to detect as some comparison with the other cells by automatic algorithm is possible. However, like all automatic methods, the diver should remain understand decisions taken by the computer on their behalf and be able to manage their dive accordingly. If the diver considers these are not appropriate for a particular type of cell failure, usually confirmed by DIL Flush Cell Check, then any individual cell can be turned off or re-enabled manually. This can be accessed from the Cells option in the Dvo screen. Algorithm Rules: a) If all cells have been disabled by the user the LSS control system is turned off. No solenoid firing will occur. b) If a single cell is below 0.15 bar or above 3.00 bar, then it will be disabled, the system denotes this with an N next to the cell. A Red CELL mv ERROR will display. To clear this error, confirm the correct cell is disabled, turn it on and turn it off in DVo. c) If after item 2, all 3 cells are disabled for the same fault, then all cells will be re-enabled, this ensures that if the O2 is very high, or very low and all the cells agree, then the O2 is probably very high or low accordingly. d) If all cells are enabled and have no faults, then each cell is checked to see how many other cells it is within 0.20 bar of. e) If all cells are within 0.20 bar of each other, then all cells will be enabled. f) If two cells are within 0.20 bar of each other and one cell is not, then the cell that is not within 0.20 bar of the others will be disabled. g) If no cells are within 0.20 bar of each other, then all cells will be kept enabled. h) If all 3 cells are disabled with the same fault at this stage, then all will be re-enabled. i) All enabled cells are then used in the PO2 averaging. Any cell disabled in these calculations will have a D or N shown against it in the O2 sensor Screen. Page 48 Vobster Marine Systems Ltd version: 1.5.2

50 Examples: Cell 1 = 0.5 bar, cell 2 = 0.60 bar, cell 3 = 0.70 bar. All cells used (rule a) Cell 1 = 0.3 bar, cell 2 = 0.60 bar, cell 3 = 0.70 bar. Cells 2 and 3 only used (rule b) Cell 1 = 0.3 bar, cell 2 = 0.60 bar, cell 3 = 0.14 bar. Cell 1 and 2 only used (rule b) Cell 1 = 0.3 bar, cell 2 = 0.60 bar, cell 3 = 0.90 bar. All cells used as no obvious fault in any single cell (rule c) CO2 Sensor failure and false reading The CO2 COMM alarm indicates that information is no longer being received from the CO2 sensor. In this instance, to reduce alarm blindness, the CO2 sensor can be turned off in the DVo menu. The diver must now carefully monitor themselves for signs of hypercapnia to replace the sensor warning function for instances of absorbent failure. The CO2 sensor can also give false high readings if moisture is present in the gas being analysed. Careful design of the VMS RED SERIES reduces this chance of a false high under normal operating conditions. If high CO2 readings are shown, these are most likely due to CO2 and not moisture. Tests have shown that the CO2 sensor can detect significant levels of CO2 before the diver detects symptoms. VMS does not recommend that the CO2 sensor isolation function is used to reject CO2 readings suspected as due to moisture. Ensure that the CO2 sensor sponge is dry before every dive. Primary screen failure Primary screen failure and the loss of dive management information is disconcerting. In this case primary LSS status monitoring can be continued via the HUD while the possible cause of the failure is established. The two causes of a blank screen are either physical screen failure in the handset / handset damage or a catastrophic head flood removing LSS data. If the HUD is still operating with SOLID GREEN and the solenoid can be heard, then it is likely that the screen has failed. Continue on CC using the ISEC for detailed PO2 monitoring and dive information with a short push of both buttons. If the HUD is inactive or showing incomprehensible LED flashing (for example all LED on or off or flashing together) then the electronics are compromised. Use ISEC to monitor PO2, maintaining PO2 manually and ascend on CC. If PO2 cannot be maintaining within safe limits manually, the OC bailout is the only option. Main battery failure The LSS is powered by three batteries, providing redundant backup against single battery failure. Should all three fail or be impaired by flood, or drop below 30% charge, the ISEC has an independent power source and can be used as above. Use of isec Under normal conditions the detailed PO2 cell info on the ISEC screensaver should be accessed once every four to five minutes. this prominent action should also be noted by buddies as evidence of proper monitoring by the diver. It is also strongly advised to trigger the dive computer function to ensure that the correct backup information to the Primary display (Depth, setpoint, current diluent) is present and that Time To Surface (TTS) calculations for each display are the same. NOTE: Even if setup is identical, TTS surface may differ slightly between Primary and ISEC due to physical variations in depths of pressure sensor for Primary calculations (unit electronics pod) and ISEC (Right chest D Ring). Page 49 Vobster Marine Systems Ltd version: 1.5.2

51 Section 5: Setup for diving. Please read this section in conjunction with detailed strip down manual for additional detail on each process. Note: A full strip down and rebuild should be part of the User course delivered by your instructor. Preparation for first dive Your unit leaves VMS after QA of all components, sub assemblies and the completed system. It is despatched boxed and ready to prepare for diving. For more information on each of these sections, please refer to the indicated manual section. please also read through full procedure before beginning. 1) Carefully remove all parts and assemblies from the shipping crate 2) Remove the rear case from the unit. 3) Charge electronics pod using banana plug connectors and observing correct polarity. 4) Using an allen key, remove the two retaining bolts securing the PO2 module and withdraw from the head. Ensure cells are correctly seated and retained by plastic clip. Check that two blue LEDs blink periodically. Charge module. 5) If new cells are required, remove from packaging and install one onto each jack connector with the white membrane pointing outward. 6) Inspect the two O rings for pinches or damage. Refit with a light smear of Tribolube on each. 7) Refit the module by pushing gently into housing and secure with allen bolts. 8) Unscrew the collar on the CO2 module, remove the sponge carrier and verify that sponge is present, dry and evenly seated in carrier. 9) Inspect O rings sealing carrier and screw gently back onto CO2 module 10) Carefully matching plastic index slot on plug to socket, slowly push CO2 plug and play connector into CO2 socket on pod. Retain with ribbed plastic collar and ensure. DO NOT use collar to force plug into socket. 11) Inspect O rings sealing CO2 module. Push the CO2 module into head until collar can be engaged on thread. Do up collar clockwise without over tightening. 12) Read and follow CO2 and O2 cell calibration procedure below. 13) Detach BOV from breathing and LP hoses and perform flow check. With mouthpiece in CC mode, ensure normal breathing is possible. Block the left and suck gently, ensuring no leak back through exhale valve. Block the right and blow ensuring no leak back through inhale valve. Block both and inhale ensuring no leak through barrel O rings. 14) Switch BOV (where fitted) to OC mode. Ensure normal breathing from OC reg. Block LP port and suck, ensuring no leaks back through diaphragm, mushroom valve, barrel O rings and retaining ring. 15) Attach mouthpiece to breathing hoses and check for damage. Repeat flow check with hoses on. 16) Attach inhale and exhale hoses to unit, ensuring exhale goes to exhale port and inhale to inhale port. Green is exhale and Red is inhale. 17) Remove base of rebreather and extract spring base and filter basket. 18) Check TPM stalk for blue flashing light at top. 19) Check all springs are correctly seated and base sits level. 20) Check base of basket is free to move and place over stalk until resting on base. 21) Fill basket according to instructions printed on side. 22) Remove, clean, examine, grease and replace sealing O ring in base of rebreather. 23) Remove dump valve cover on base, remove, clean, examine, grease and replace O ring. 24) Check setting of auto dump valve - this is a personal setting to each diver, but a good starting point is to close and open four clicks. Page 50 Vobster Marine Systems Ltd version: 1.5.2

52 25) Replace cover and screw until closed, then back off until LP fitting lines up with spring retaining pin. 26) Place spring base and basket assembly into rebreather base and press down until all five latches engage and all five springs are compressed. 27) Check condition of triple lip CO2 seal in flow cone. Lips should be totally free of sorb or debris. Lightly grease. 28) Avoiding HP cables and senders, maneuver base / filter assembly into the rebreather body and align base to engage bayonet fitting on body. 29) Pull down spring loaded retaining pin and gently twist base clockwise. Listen for latches to release and push filter into CO2 seal. Release retaining pin when aligned with socket on Right side of body. Take care not to trap hoses during this process. 30) Fill, analyse, mark and fit diving cylinders to the unit. Read Operational Configuration section for more information on diluent selection and refer to course materials from your agency. 31) Check counterlung is not trapped by any part of the rebreather body or bottles. 32) Attached balance tube to OPV cover and ensure open end pushed through case close to backplate. 33) Check hoses and cables are neatly routed. 34) Replace case. Check counterlung is not trapped. 35) Locate the primary handset with wrist strap. Press and hold both buttons until VMS screen displays. Check the first status screen displays good comms and battery levels for all sensors. 36) Continue to PreBeathe if required or turn off with long hold both buttons. Calibration of O2 and CO2 sensors See also section in unit strip down on O2 cell calibration. Calibration of sensors is crucial to accurate tracking of gas breathed by the diver and should be performed routinely or after environment change, but not over frequently. The LSS is able to perform accurate calibration of the Partial Pressure Oxygen (PO2) cells in ambient air. This has particular importance on the ease and accuracy of achieving calibrated PO2 cells. The LSS is able to measure atmospheric pressure during calibration and make the appropriate calibration adjustments for the PO2, even at altitude. Cell health is also logged and cells should be changed if mv readings drop below 8.5 mv. When performing PO2 cell calibrations, it is important the calibration gas and ambient pressure are known. By using ambient air as the calibration gas this is known accurately. Both the primary and ISEC units must be calibrated during this process. The primary prompt to begin calibration automatically when cells are refitted. Calibration can be also be initiated from the SETUP menu. Whichever method is use, the ISEC calibration must be initiated manually. 1) Primary handset actions. From the surface status screen, access the menu with a short R push. Scroll to SETUP and enter. Scroll to Air Cal and select. Read the warnings about incorrect calibration and follow instructions to remove exhale hose from BOV. Breathe as directed for two minutes. At the end of this time the cells mv readings will be calibrated to by the unit, based on ambient pressure. 2) ISEC actions. While breathing, turn on ISEC and access computer functions with a short push of both buttons. Scroll L or R until the O2 cell info screen is seen. Enter this and select CAL. The ISEC will now for acknowledgement that FLUSH (breathing as directed by the Primary) is taking place. Once the readings are stable on both handsets, acknowledge STABLE and then EQUALISE to allow the ISEC to set all readings to 0.21 Bar for the mv readings at that time. CO2 cell calibration must be carried out with the sensor face darkened and outside. Do not calibrate the CO2 sensor in a building as even seemingly insignificant levels of CO2 can affect calibration. Any surface errors are magnified at depth and can cause dangerous levels of CO2 to be under reported. First, access the menu from the STATUS screen with a short R push. Scroll through the menu to CO2 and enter this. Allow the sensor time to warm up, after which the Cal option will become available. Ensure the exhale hose is removed from the BOV and the CO2 filter is removed from the rebreather. It is also acceptable to calibrate the CO2 sensor before fitting the CO2 filter. Breathe on the mouthpiece in CC mode to draw fresh air over the sensor and activate Cal. Once complete the sensor will display a cell health value and is ready to use. At this point a CO2 reading of mb CO2 should display. It should read 0.00 mb after pre breathe is complete. Page 51 Vobster Marine Systems Ltd version: 1.5.2

53 There is no CO2 cal function on the ISEC - it does not monitor CO2 Flow check Remove corrugated inhale and exhale hoses from the mouthpiece, along with LP OC Bailout supply hose (if fitted): 1) Examine mouthpiece and cable tie for damage and secure fit. Pay particular attention to where the rubber mouthpiece runs over the lip of the mouthpiece port as small splits here can be hidden, but cause significant problems underwater. 2) Breath from the mouthpiece in CC mode, with selector switch horizontal. There should be no breathing resistance and operation of inhale / exhale valves heard. 3) Block the L valve port and inhale gently. No leakage past the exhale valve should be detected and no noise heard. 4) Block the R exhale valve port and exhale gently. No leakage past the inhale valve should be detected and no noise heard. 5) Block both ports and inhale firmly. There should be no leakage in past barrel O rings. 6) If a BOV is fitted, switch the selector to OC mode. Breathe from the bailout reg - it should be possible to draw gas through the reg with some resistance. 7) If a BOV is fitted, Block the LP hose port. Breathe from the reg firmly. There should be no gas flow and no noises from diaphragm and cover. 8) Re-connect mouthpiece to hoses using the two white C clips. ready for unit assembly. If any of these tests are failed, refer to Unit Troubleshooting and Disassembly section. Do not begin a dive with a known fault. Loop Integrity Once the rebreather is assembled, it is crucial to check that it is not leaking. This is accomplished by applying a negative pressure and confirming that the unit can maintain this negative in loop. If no gas can enter through leaks, neither can water enter the loop and disturb filter function or cell readings. 1) First ensure that HP cylinders are connected, but turned off and drained. Isolators for ADV and Solenoid are open. 2) If a BOV is fitted breath briefly on the BOV on OC mode to empty the OC LP line. 3) Operate the O2 manual addition button to empty the O2 pipework. Page 52 Vobster Marine Systems Ltd version: 1.5.2

54 4) With the mouthpiece in CC mode, breathe in through the mouth and vent through the nose. Repeat until significant pressure, but not discomfort is felt on inhalation. It also helps to manually compress the corrugated breathing hoses, closing the corrugations. While holding the negative, switch the mouthpiece to close the loop. 5) Allow the mouthpiece to hang from the breathing hoses and watch carefully for movement. 6) Time 1 minute. 7) At the end of the minute, the mouthpiece should not have dropped and a loud sucking sound should be heard when switched to CC as remaining vacuum is released. 8) Mouthpiece dropping? little or no vacuum release after one minute indicate a leak or leaks. Refer to Troubleshooting Loop negative. Analysis of Gas It is a golden rule of rebreather diving that all gasses should be analysed and marked before fitting to unit. Analysis should be carried out using a properly calibrated Nitrox or trimix analyser according to the manufacturers instructions. NEVER assume that even Air is Air and Oxygen is Oxygen. Failure to confirm cylinder contents is dangerous and each diver should analyse only their own cylinders. Marking should be give both contents and MOD - the depth where the O2 contents of the cylinder reaches 1.6 Bar. Always ensure that analyser cell is in date. Always ensure analyser has been calibrated. Do not analyse in the rain. Gauges The unit incorporates HP sensors into it s LSS and as such does not have traditional SPG. To check HP sensor function and cylinder contents, turn on unit, abort pre dive and check surface status screen for cylinder icons. White outlined icons with contents registering indicate normal function and contents. Red contents indicates good sensor function but low resource levels. Purple outlines indicate no data communication. In this state any contents indicated cannot be regarded as accurate. During startup a yellow outline may also be displayed, indicating that sensor comms are good, but contents information is updating. Wait until white outline is restored before using information on contents. NOTE: If PO2 data is not shown, HPO2, HPDIL and TPM data will not be present. Stack filling and function 1) Remove the top nut and canister lid and inspect for damage. The lid is removed by twisting ¼ turn. 2) Remove any excess Sofnolime stains from the canister components with warm, soapy water and then rinse in fresh water. Allow to dry. 3) Fill the canister in a well-ventilated environment. Raise the Sofnolime barrel at least 200mm above the canister to allow dust to blow away as you fill. Fill to the top of the canister, making sure Sofnolime is at an even depth across the canister. 4) Pack the Sofnolime by tapping the sides for at least 1 minute. 5) Fill to top again. 6) Lift the outside tube by approximately 20 mm level with top of white tabs to allow the base to drop and the Sofnolime level to fall inside the tube again. 7) Refill with Sofnolime to the top. Tap down as required until you can fit the lid. Refit the lid. 8) Screw down the top nut. Page 53 Vobster Marine Systems Ltd version: 1.5.2

55 9) Wipe any dust from the canister. Close eyes and blow dust from below basket. 10) Look up into the canister head and inspect the flow cone seal. Clean and re-grease as required. This is the primary CO2 seal and it is vital that this seal is in good condition. Diving with a damaged seal may be fatal. 11) Insert the filled canister into the canister base making sure the five clips are engaged. 12) Ensure transmitter cap is clear and blue light blinks. 13) Refit the canister base into the rebreather. The five clips will automatically disengage and load the canister into the seal. 14) Dispose of old absorbent in the normal household waste. Do not leave it lying around for animals to ingest. Filling instructions are also found on the side of the canister tube. Battery charging The unit uses Lithium ion batteries. These rechargeable batteries are very efficient and provide many years of reliable operation. Rechargeable Lithium batteries can be recharged at any time and do not have a significant memory affect, which would otherwise cause unreliable battery operation. The batteries are UL listed and are double sealed to reduce the chance of leakage to a minimum. As extra confidence, the battery pack includes 3 separate batteries to achieve operation even under multiple battery failure scenarios. The battery reserve alarm will indicate as the unit switches to the 3rd battery giving 1/3rd battery life remaining. At this point, the ISEC will switch to using it s onboard battery. Two of the batteries can be considered as main batteries. These are the first to be used during normal operation. When these two batteries become low, the third back up battery starts to be used. Failure of any battery will not affect the operation of the others. Main battery levels are displayed as a vertical icon on the R of surface status screen. To recharge the main batteries, connect the banana plug charger to the head taking extreme care to observe correct polarity. This will charge both main and ISEC batteries. The ISEC display has an independent rechargeable battery which is charged as the main unit charges. The ISEC display battery will display a battery alarm when it is charging or if the battery is low. The user should keep the batteries recharged and topped up to ensure there is always maximum capacity for any dive. If the unit has become completely flat, it can take up to 12 hours to recharge fully, with the first wakeup stage being slow. Page 54 Vobster Marine Systems Ltd version: 1.5.2

56 Note: Connecting the charger is very straight forward. With the charge unplugged from the mains supply, insert the red plug in the charge pin marked with the (+) symbol and the black plug in the charge pin marked with the (-) symbol. Then plug the charger into the mains supply. After a short period (less than 1 minute) the charging screen will appear on the primary handset. Once charging is complete, unplug the charger from the mains supply and remove the plugs from the unit. Weighting As the counter-lung inflates the diver may experience movement in the LSS. This is minimised by tightening the harness or adding harness weights and running the unit with minimum loop volume. If the LSS is allowed to move on the divers back, a change in breathing resistance may be noted. With back, mounted units it is important that the counter-lung is as close to the divers back as possible. The LSS has a weight pockets for a trimming weight mounted on the case. It is important to perform weight checks in confined shallow water with minimum levels of bailout gas prior to any open water diving. Harness Positioning When adjusting the harness try and imagine that the center of the counter-lungs should be within +/- 100 mm of the tip of your sternum to give an optimum breathing performance. While the harness must be comfortable it should not be loose. The harness will sit differently on land compared to when you are in the water. The crotch strap should be a snug fit to prevent the unit riding up when in an inclined position. Page 55 Vobster Marine Systems Ltd version: 1.5.2

57 Section 6: Operational configuration Diluent selection Diluent selection will be covered by your training agency, but should always have a PO2 significantly below intended setpoint at maximum dive depth. Failure to plan for this removes the ability to DIL Flush Hyperoxic loop conditions effectively. DIL Po2 of 1.0 and 1.1 Bar at max depth are common selections when planning CCR dives. The use and discussion of surface Hypoxic diluents varies between training agencies. The inert gas components of the diluent should also be carefully calculated to deliver an appropriate END for breathing gas. VMS recommends that END should not exceed 36 m. Diluent should always have a maximum of 10% O2 and a min of 80% He for a max depth 100 m dive. You should never use a diluent with less than 5% Oxygen. Gas Endurance Gas endurance is as crucial to the unit as open circuit diving - without O2, the benefits of accelerated deco are lost and task loading to stay on the loop significantly increases in DIL SCR mode. Without DIL, the breathable volume of the loop cannot be adjusted and an immediate switch to OC is required, with an ascent to increase the volume before switching back to CCR mandatory. O2 Endurance calculation. The maximum volume of O2 available to the diver is the cylinder rated working fill pressure of 232 Bar multiplied by the volume of 2 litres. This gives a volume of 464 litres of O2. Leaving the reserve level of 50 Bar from this leaves 364 litres. During normal diving the metabolic rate of the diver will use 1.78 litres per minute. 364 litres divided by 1.78 litres per minute, gives a nominal duration of 204 mins. As the metabolic rate of a diver is independent of depth, this gives a maximum runtime of 204 minutes, split in any combination between bottom time and ascent time. 204 minutes is well in excess of the rated CO2 filter duration on deep dives so O2 should not be a limiting factor on an error free dive beginning with full cylinders and a new scrubber. However for long duration shallow dives you may need to consider carrying off board oxygen reserves. Note: Problems that result in a loss of O2 volume may require a switch to a pre planned contingency strategy. Diluent endurance calculation. Under normal diving conditions, DIL is used to inflate the loop at depth compensating for the effects of Boyles Law. Considering the loop volume of approximately 10 litres and the maximum CE rated depth of 100m, this would require 110 litres of volume corrected to surface pressure. Compared to the available volume in a fully filled cylinder of 464 litres, corrected to remove a 50 Bar reserve to 364 litres, this inflation will not use all the Diluent and should only happen once for a normal dive. The second use of Diluent is for sanity breaths during the switch from CCR to Bailout OC. On a 100m dive, the available volume for this is 364 litres litres used for loop inflation. This leaves 254 litres. VMS recommends that only two sanity breaths are taken from the BOV prior to completing the switch to Bailout OC. The average human inspiratory reserve volume is 3 litres for men, meaning each breath at 100m requires 33 litres of gas. The volume of diluent remaining is adequate for 7 breaths, or two switches to and from OC bailout. Dives or scenarios requiring more than this, or when the wing is used for buoyancy at extreme depth mandate the use of off board diluent via the gas addition port on the gas block. Note: VMS recommends that ALL dives are begun with a full diluent cylinder. We also strongly recommend that for any dives beyond recreational limits you consider alternative gas supplies for wing/ suit inflation, such as a separate suit inflation cylinder, or additional off board gas. Bailout selection Page 56 Vobster Marine Systems Ltd version: 1.5.2

58 While the exact gas requirements for any type of diving are a matter of personal choice based on your LSS certification level and training agency, it is vital that a breathable open circuit bailout is carried at all times for all depths of the dive. The following is offered as a guide when configuring the unit for a range of diving conditions. This should be used in conjunction with the recommendations from your diver training agency. Careful thought should be given to OC bailout gasses. Switching to OC bailout at depth could be due to CCR failure, or it could be while resolving a CCR issue, prior to returning to the loop once safe to breathe. In either case, switching to an OC Bailout with a significantly deeper END would impair the diver either to make a safe ascent or to troubleshoot CCR issues. Use of a bailout with an END similar to the diluent END is recommended. OC bailout should be a gas which is similar to that breathed in loop. OC bailout will result in an increase in decompression obligations and bailout gas should be planned to minimise this increase. Simply choosing air for convenience is not recommended. Note: Never use a BOV in such a manner as it is only connected to a breathable source via the diluent gas block, ie in the case of off board gas. The gas flow through the gas block may be insufficient to operate a 2nd stage regulator at depth under certain conditions. The prime sanity breath gas source should be the in-board gas cylinder which must be breathable at depth and be of sufficient volume to allow time to switch to an off-board regulator. Bailout gas volumes should be calculated based on the depth of the dive and the ascent gas requirements. Cylinders can be positioned on D ring attachment points on the harness. Thought should also be given to breathing rate in the event of a CO2 event - do not use your personal best lowest ever SAC rate to justify cylinder size or bailout gas volume. Example OC Bailout calculations It is crucial to include OC bailout planning when planning CCR dives. The switch to OC gas should not impair the diver from a narcosis point of view and any increase in decompression penalty needs to be planned within the team. This is particularly important when trying to resolve differences in ascent plan in mixed teams. VMS recommends that CCR divers aim to buddy other CCR divers to simplify this planning. The following example has been calculated as an example to demonstrate OC Bailout volume and should not be used for actual diving. Consult your training agency materials for guidance on choosing Diluent gas, OC Bailout gas, END, stop depths, ascent rates and other relevant baseline assumptions for your own diving. Example dive 48 m, 20 min Diluent selection is based on: 1) Diluent PO2 of 1.1 at 48 m, giving an FO2 of 19% 2) Diluent END of 24m at 48 m, giving an FHe of 35% OC Bailout selection is based on: 1) The diver beginning ascent immediately allowing a max PO2 of 1.6 Bar, giving an FO2 of 28% 2) An END of 24 m, giving an FHe of 25% Programming 19/35/46 in as Diluent and 28/25 in as OC Bailout allows use of the dive planning function to derive the following ascent for Plan A, no rebreather failures. Depth Stop length Runtime Gas required A) 6m B) 11 min C) 38 min D) 11 litres O2 E) 9m F) 1 min G) 27 min H) 1 litre O2 Page 57 Vobster Marine Systems Ltd version: 1.5.2

59 I) 12m J) 1 min K) 26 min L) 1 litre O2 M) 15m N) 1 min O) 25 min P) 5 litres O2 Q) 48m R) 20 min S) 20 min T) 20 litres O2 This ascent requires only a small amount of O2 to replace that metabolised by the diver. Switching to the simulate function with the same gasses and dive parameters allows us to simulate the dive until 20 mins elapsed dive time, then perform a switch to OC and display the new decompression requirement on OC 28/25 Trimix, based on a breathing rate of 25 litres per minute. Depth Time Runtime Gas required 6m 36 min 66 min 1440 litres 28/25 9m 4 min 30 min 190 litres 28/25 12m 1 min 26 min 55 litres 28/25 15m 1 min 25 min 62.5 litres 28/25 48m 20 min 20 min CCR To this must be added the gas required for the ascent itself. Ascending from 48m to the surface at 10 m per minute requires 425 litres of Trimix 28/25 in addition to the gas for stops as above. The total OC bailout gas required is 2173 litres of 28/25. This can be carried in a variety of configurations according to diver preference and qualification level, but is interesting to consider the fill pressure for the single 11.1 litre cylinder carried by user level CCR divers who may be contemplating this dive as progression towards increased depth. The fill pressure required in an 11.1 litre cylinder is Bar. This is beyond the realistic limit of this cylinder, especially when considering any additional delay at depth, delay on ascent, increase in breathing rate, increase in stress or the effects of CO2, which other than loop flood, is a main reason for OC bailout. Use of air in a convenient 7 litre cylinder is obviously a far worse choice - the decompression times are extended and available gas is reduced, plus narcosis prevents the ascent plan from being followed as efficiently. Options to solve this problem are: 1) Robust, practiced team bailout plan. 2) Carrying additional OC decompression gas for switching to in the shallows (eg 50%). This technique is taught buy most agencies at the Normoxic CCR level. WARNING: The above example is for illustration only and should not be used as a dive plan. Consult your training agency for more detail on gas planning, gas configuration and team skills to complete your own plan. Page 58 Vobster Marine Systems Ltd version: 1.5.2

60 Now if we look at the same bailout, but based on an elevated breathing rate of 40 l/min Switching to the simulate function with the same gasses and dive parameters allows us to simulate the dive until 20 mins elapsed dive time, then perform a switch to OC and display the new decompression requirement on OC 28/25 Trimix, Depth Time Runtime Gas required 6m 36 min 66 min 2304 litres 28/25 9m 4 min 30 min 304 litres 28/25 12m 1 min 26 min 80 litres 28/25 15m 1 min 25 min 100 litres 28/25 48m 20 min 20 min CCR The total volume of gas now required to bailout is 2796, so at 200 bar 14 Ltrs. This realistically means you would need to carry two cylinders to bailout in the scenario if you have elevated breathing. Page 59 Vobster Marine Systems Ltd version: 1.5.2

61 LSS gas programming Once dive planning is complete with set points, diluents and bailouts gasses identified, filled and confirmed to match the plan, these gasses and set points can be entered into the LSS and ISEC. Primary handset programming Existing gas menu can be checked with a short R and scrolling through the menu to gas list. To edit this list, exit the menu back to surface status screen and use a long L to enter the Gas menu branch. A short push Both now access the DIL selection where changes can be made and additional diluents added. Gas numbers 1 to 4 are configurable as diluent gases. DIL is displayed against the gas number for these gases. One DIL must always be turned on and the default gas when shipped from VMS is DIL 1 AIR. To edit this do short push both to change gas composition and MOD. To add a gas, short push both as in edit, scroll to gas number and increment to desired number. Turn this gas ON and edit as required. Gas numbers 5 to 8 are configurable as the open circuit bailout gases. OCB is displayed against the gas number for these gases. The edit and enabling process is the same as for DIL gasses. Once programming is complete, exit the edit settings and exit the gas screen. The unit will now prompt for initial DIL confirmation. Confirm that this is the DIL currently active on the unit and save. The next screen prompts for confirmation of setpoint to be applied to this gas. Choices here are between Manual (including specifying a manual setting) and Auto. Choosing Auto will apply the settings from DVo. These identify the Setpoints for depth, deco and how the transition between depth and deco setpoints is managed. At least one diluent gas and one bailout gas must be configured and set to ON for each dive. The adjust screen can not be exited and the LSS will not turn off until this configuration has been made. The default state for the gas configuration is Air. The default configuration is for DIL gas 1, and OCB gas 5 to be active. When the unit is switched to open circuit bailout during a dive, the diver will be prompted to accept the open circuit bailout gas configured for use at their current depth based on the maximum operating depth configured for each gas. The user can go into the gas configuration menu and adjust both diluent and bailout gases while diving. ISEC programming The ISEC must be programmed independently from the Primary. There is no automatic update possible between handsets. NOTE: Failure to match gasses programmed between handsets will cause dangerous differences in decompression required in the event of relying solely on ISEC following Primary failure. To access the gas menu, scroll left or right from surface screen until the ata a glance gas screen is displayed. Enter this with a short push both. Gasses can be edited with a further short push both and all active gasses are displayed. Each gas can be designated for CC use or Bailout in the square box. The round radio button indicates the gas currently selected - this should match that on the primary. After gasses and MOD are configured, complete the programming by confirming the setpoint for the dive. This MUST match either the Manual setpoint selected on the primary, or the Depth Auto setpoint setting in DVo on the primary. Page 60 Vobster Marine Systems Ltd version: 1.5.2

62 NOTE Setpoint change for deco must be made manually on the ISEC during the dive. Setpoint Selection Setpoint configuration The unit can run in auto setpoint mode, or manual mode up to 1.6 Bar PO2. Manual mode allows the user to adjust the LSS setpoint in 0.05Bar steps. It allows adjustment of the auto setpoint maximum of between 1.0 Bar to 1.3 Bar. In addition to the main diving setpoint, there is the ability to choose an additional setpoint for use during decompression. The value of this setpoint, as well as the depth at which this setpoint is activated can be set. If Auto depth is set, then the decompression setpoint is switched to as soon as a decompression stop is reached. Alternatively, a decompression depth can be chosen that the diver needs to have ascended to (within 2 m) before the decompression setpoint is activated. Finally, the decompression setpoint can be disabled. The decompression setpoint can be chosen between 1.0 Bar to 1.6 Bar. The adjustment of the auto setpoint for dive and decompression are done in the second of the Dive Option Dvo screens. To get from screen 1 to screen 2, use the short press of both buttons to move around each field. Use the + and to change the setpoints to the desired values. When adjusting, consider the CNS and other oxygen toxicity issues, together with optimising decompression times, as provided in your rebreather training course. If in doubt on values to choose, consult your rebreather diving instructor and training documentation. If a switch is made to manual setpoint higher than the auto settings during the dive, followed by a switch back to auto setpoint, then the manual maximum will be used instead of auto settings when reverting back to auto mode. This feature is of particular use in cave formations where topography challenges automatic setpoint maintenance by the LSS. Auto setpoint changes Auto setpoint intelligently chooses an appropriate setpoint for the current depth and dive duration. The Auto Setpoint flow chart describes the mechanism in detail. The main reasons and design criteria for the auto-setpoint adjustment system are: 1) Remove tasks from the diver for safe and optimised diving. 2) To ensure that the setpoint is not set too high too quickly and thus cause a severe spike in PO2 should the diver continue descending with a high PO2 already in the breathing loop. 3) To ensure an optimum setpoint is used to reduce the on-gassing of inert gas in the body 4) To ensure an optimum setpoint during decompression. 5) Oxygen gas is not wasted in trying to achieve an elevated setpoint not achievable at the current ambient pressure eg 1.2 Bar at the surface. Before diving, in surface mode, the unit will operate to a setpoint of 0.4 Bar. Because the solenoid algorithm is pre-emptive, the unit will continue to inject until 0.03 above setpoint if you are not breathing on it. When the LSS enters dive mode ( see dive mode on how this occurs ), the unit changes setpoint to 0.7Bar minimum. As the diver descends beyond 12 m (40 ft) the setpoint is incrementally increased based on the maximum depth up to a maximum setpoint of 1.2 Bar at 33 m. If the diver descends beyond 33 m the setpoint will not be further increased. Page 61 Vobster Marine Systems Ltd version: 1.5.2

63 In addition to the incremental adjustment, if the maximum depth > 20 m and the dive duration > 5minutes, then the setpoint will be immediately adjusted to Auto setpoint maximum. If decompression stops are required, the setpoint will be kept at Auto setpoint maximum automatically. On ascent, and where there are no decompression stops remaining, as the diver becomes shallower than 4 m, the setpoint will return to 0.7 Bar. The setpoint will also revert back to 0.7 Bar at a depth shallower than 2 m above the shallowest programmed stop, preventing addition of O2 exacerbating buoyancy problems. Setpoint changes: ascents & descents When a setpoint is changed, the rebreather will require time to adjust the PO2 to the new level. Likewise, during ascent and descent, depth changes immediately change the PO2 in the breathing loop, and the LSS requires time to adjust the PO2 accordingly. Therefore the LSS detects both of these types of normal diving disruptions to the PO2, and downgrades the alarm type during these transitions. For a setpoint change, 2 minutes is allowed for the setpoint to be achieved. For a depth change of > 7.5 m (22 ft) per minute up or down, 1 minute is allowed for the PO2 to recover after the end of the depth transition. This system reduces the alarm blindness without reducing the safety of the system. PO2 Hypoxic and Hyperoxic alarms will still create the highest level of alarm during the transition, but a breathable mixture inside these limits and appropriate to the depth change or setpoint change detected will temporarily down grade the alarm. Page 62 Vobster Marine Systems Ltd version: 1.5.2

64 CCR Dive planning functions The LSS can be used to plan dives - from the surface screen use a short right to enter the menu and scroll to dive plan. Here depth and bottom time for the required dive can be selected. A long push now displays the dive screen for this dive and long R will display the decompression required with currently active gasses. Re running the plan having changed gasses as above allows the diver to explore operational options. OC Bailout planning Bailout planning requires the use of the simulate function. Select the same depth and time as in dive planning, enter the simulate and allow dive time to elapse to the end of bottom time. Now use a long L to switch to OC, return to the simulate screen and a long R will display the bailout schedule for currently selected gasses. Use this profile to determine volumes of each bailout gas required and reserves carried by each team member or staged. ADV use The ADV automatically ensures a breathable volume of gas in the loop. It is important during task loaded dive phases such as descent. It also provides a hands free method of DIL flushing. However, inadvertent use at depth or on ascent can cause variations in loop PO2 and require subsequent O2 injection. The ADV can be disabled using the isolation slider on the diluent gas block for additional PO2 control on ascent. Loop volume can now be fined tuned with the manual addition of DIL. It should also be noted that the ADV should not be used if you need to work lying on your back, as this orientation could cause the ADV to freeflow. In this circumstance the ADV should be deactivated and manual addition used to maintain loop volume. Page 63 Vobster Marine Systems Ltd version: 1.5.2

65 Section 7: PreDive check sequence The PreDive check sequence is used after unit preparation and assembly to confirm that each step has been completed and is functioning correctly. It is not the best tool for diagnosing non functioning equipment. If all preparation steps have been completed, the PreDive check sequence including pre breathe will take under 10 minutes to complete. Step by step confirmation of unit readiness From the surface status screen, use a short push of both buttons to access predive screen. Subsequent screens will prompt for actions and confirmations to complete the predive. The sequence is unit prompted to reduce the chance of human error, but certain actions - flowcheck and loop negative affirmation rely on honesty from the diver. The sequence begins by confirming cell health and calibration, continues through flow check and negative loop check, HP sensor confirmation and O2 / DIL level check. It prompts for diver confirmation of manual injection for O2 and Diluent, plus confirmation of filter use or renewal. Pre-breathing the LSS prior to diving is the most important of the Pre-Dive checks. It MUST be completed with the nose blocked for the entire duration. Pre breathe confirms the following: 1) CO2 filter is operational. If it is not operating correctly, e.g. there is a bypass of CO2, then any effects such as passing out, hyper-ventilating or dizziness can be treated properly in safe dry conditions. There is a timer on the PREBREATHE screen of 5 minutes. The screen can not be exited (unless by ABORT) until 5 minutes has been completed. The Temperature Profile Monitor (TPM) must also register a temperature difference across the filter of at least 7 C (12 F). If TPM is disabled in the Dvo screens this 7 C (12 F) test is not required. This can occasionally be useful when there are abnormally high or low ambient temperatures. It can also be used to allow completion of the predive screens if there is a communication failure with the TPM. The LSS is tested during the 5 minute period to determine if there is a CO2 breakthrough independently via the CO2 monitor or physiological symptoms. The TPM can be considered as an improvement in system checking, but not a vital life support system component. The temperature profile is shown on a bar graph. If the temperatures do not vary significantly across the filter, then the filter may be near the end of its life, or fitted badly, flooded or even not fitted at all. Check the filter. If in doubt, replace the filter. Bar graph colours are based on the temperature difference across the filter: Green Yellow Yellow Red > 10 C (18 F) > 7 C (12 F) overall temperature of filter > 30 C and 5 minute pre-breathe done < 7 C (12 F). Always complete the pre-breathe diligently. If you do not pre-breathe correctly then the safety check of temperature difference across the filter will not be achieved. If any adverse symptoms are felt or seen by other people during this time, then stop breathing and check the filter and seal. Do not dive! The extra yellow condition for overall temperature of filter > 30 C and 5 minute pre-breathe done is included for common condition of high ambient temperature and filter temperature. This happens after a dive when the filter has not been used for 10minutes. The heat in the filter spreads out across the filter. This coupled with high ambient temperatures can make it difficult to reach a significant temperature profile during the pre-breathe period. If the diver is confident that the pre-breathe has been done safely and no adverse symptoms experienced, then the pre-breathe can be accepted in a yellow condition to continue with the remaining pre-breathe states. Pre-breathes should be conducted with the nose blocked. 2) O2 injection is occurring successfully. As O2 from the loop is metabolised, the drop in PO2 is detected and the solenoid fired to replenish. Maintenance of 0.4 Bar PO2 at the surface can only be achieved for five Page 64 Vobster Marine Systems Ltd version: 1.5.2

66 minutes if all sections of the O2 gas pathway and PO2 monitoring are functioning correctly. Both Primary and ISEC should be checked to ensure that 3) CO2 monitor readings remain normal. PreDive Screen shots Shortened check availability Once a predive has been completed, the unit will turn off after 8 minutes if not dived. Turning on within one hour will enable a shortened sequence of checks to be completed. Presence of a CO2 monitor also allows the pre breathe to be shortened to 2 mins if the temp is in yellow status or one min if in green. Section 8: Troubleshooting Cell mv readings Cell errors can be diagnosed using DIL flush cell check while underwater along with mv readings from the ISEC. On the surface a healthy cell should read around 9-11 mv while in 21% O2 or Air. If a cell appears to be giving a different reading, there are two possibilities. Either the cell is faulty, the connection is faulty or the PO2 block post is faulty. Examine the cell for moisture or damage, examine the Page 65 Vobster Marine Systems Ltd version: 1.5.2

67 jack connector for dirt and clean if needed. If the problem persists, swap the cell onto a different post and check readings. If the error is on the new post, then the cell is faulty. If a previously healthy reading cell is now displaying an error on the original post, then the PO2 block is faulty. It is important to ensure that the PO2 block is fully charged. Once the cell has been identified, replace the cell and check for resolution of the error. Mouthpiece and flow check fail issues If the flow check fails and gas can be drawn back through the exhale valve or pushed through the inhale valve, the mushroom valves, valve carriers and O rings must be inspected for dirt or damage. First, unscrew the ring retaining the CC selector switch. Gently pull the barrel free. Avoiding contact with the mushroom valves themselves, gently push the valve carrier free and examine the valve and O ring for damage. Remove, clean and replace the thin O ring. If either the mushroom valve or O ring are damaged, replace them. Look under the valve by carefully lifting the side of the valve up and remove any slime or debris gently. Do not damage the valve or valve seat. The carrier can be refitted by ensuring it is absolutely square to the housing and pushing evenly on the rim. Any bulging of the O ring must be corrected to achieve a good seal. It is important to ensure that you put the valves in the correct way round when you put them back into the BOV. Fig 1 below shows the exhale side, note (1) the face side of the mushroom valve is visible, (2) the dive select switch. Fig 2 below shows the inhale side, note (1) the stem of the valve and the spokes of the valve carrier are clearly visible, (2) the LP hose connection for the BOV. Fig 1. Fig 2. Inspect and replace the barrel, then repeat the flow check test listening carefully for gas leaks. Loop negative - leak detection If the mouthpiece drops during the one minute long negative check, gas is entering the loop. This leak should be fixed before diving. First, repeat the check with both sliders shut to determine if the leak is in the loop, or the gas supply pipework. If this check is good, then repeat opening first the O2 and the DIL sliders to diagnose which set of pipework is leaking. Page 66 Vobster Marine Systems Ltd version: 1.5.2