4.4/ RLE 5: Volume-flow controller, continuous How energy efficiency is improved Enables demand-led volume flow control for the optimisation of energy consumption in ventilation systems. Areas of application Exhaust air control in laboratory fume cupboards, as well as supply and exhaust air control in laboratory rooms and clean rooms. Hospital wards or operating theatres. Properties Static differential pressure detection with capacitive measured value acquisition Can be used in areas with dirty or contaminated exhaust air Highly accurate measurement of differential pressures with measuring ranges up to 400 Pa Infinitely variable adjustment of measuring range for optimal adaptation to particular application Available in calibrated version for pharmaceutical applications Ideal combination is with RLE 50 F00 or NRT 00 Fail-safe control in the case of critical applications Technical description Power supply 4 V~ Adjustable differential pressure measuring ranges...00 Pa...00 Pa 4...400 Pa control algorithm Output signal 0...0 V for Actual volume flow value Damper drive output signal Input signal 0...0 V for Remote setpoint adjustment Priority control via switch contacts Adjustable zero point Type Setpoint range: air volume % easuring range Δp (span = 00%) Pa Weight kg RLE 5 F00 0...00...00 0,8 RLE 5 F00 0...00...00 0,8 RLE 5 F00 0...00 4...400 0,8 Inputs:- Command variable w 0...0 V, R i = 00 kω Limitation min 0...00% (variable) 0...00% Limitation max 0...00% (variable) Room pressure signal w 5 ± 5 V, load 00 kω Setpoint shift Δ % ) 5 +5 Ext. contacts: Damper Closed 4 V~, 5 ma Ext. contacts: Damper Open ) 4 V~, 5 ma max. min. Y0694 00 % Air volume 0 0 Command signal 0 V Setpoint limitation 0 V Actual value xi span=50 % span=00 % 0 0 Pressure difference Δp 00 % easuring span B0695 Power supply 4 V~ +5/ 0%, 50...60 Hz Permissible pressure:- Power consumption VA operating range p stat 0... kpa Accuracy of root extraction % of 00% low-pressure connectors 5 kpa easuring span 50...00 % Δp Ambient temp. 0...40 C (variable) Ambient humidity < 90 %rh Outputs:- Degree of protection IP 44 (EN 6059) for actuator 0...0 V, load > 5 kω actual-value signal 0...0 V, load > 5 kω Wiring diagram A 080 P-band 00...900% Dimension drawing 004 Integral action time...0 s Fitting instructions V 50596 Control action A & B ) Damper Open until max has been attained ) Act as minimum limitation for w 74400 04
4.4/ RLE 5 Fitting note The controller should be fitted on vertical walls only. B005 Operation aster The pressure difference created at an orifice plate or a dynamic-pressure sensor is converted into a flow-linear signal by a root-extraction transducer 8. The command variable signal (e.g. from a roomtemperature controller) is limited by the minimum and maximum adjuster, and compared to the actual value of the air volume. Without the command signal w, the minimum adjuster acts as a setpoint adjuster Xs. The control deviation is converted by controller 9 into a continuous signal which is suitable for modulating motorised drives with an operating time of >,5 s for 90 rotation. The external switching contacts S (OPEN) and S (CLOSED) allow the damper to be operated with priority. The 'OPEN' function opens the damper until max is attained. The span adjuster allows the transducer 8 to be adapted to the desired pressure difference. If both contacts S and S are activated (closed), then S (close damper) has priority. If the command variable signal w falls below 0,5 V, and if the limitation min is set to 0%, the damper is closed with priority. If required, zero 5 can be used to set the zero point of the pressure sensor. If no setpoint shift is required, the adjuster Δ 4 should be set to 0. Slave Proportional-integral controller with one input (w ) for setting the setpoint by the master, and with another input (w ) for linking a room-pressure controller's signal. The function is the same as that of the master but the setpoint limitation must be set to 0% min and 00% max, since this is set by the master. The adjuster Δ 4 is used to set the parallel shift of the curve. When external control is in operation, the value Δ % set on the adjuster becomes the minimum limitation. Block diagram PD 4 w Δ V : T V w S %V min max 5 8 6 7 Xp; Tn 9 Δ p span zero S y xi B046 74400 04
RLE 5 4.4/ Wiring diagram 4 V~ RLE 5 zero span x x i min. max. w Xp Tn Controller Alternative: RLE 5 RLE 5 RLE 5 0...0 V 0...0 V (X sv ) 5±5 V : (X srd ) 4 V~ 0...0 V 0...0 V 0 8 9 4 5 6 7 4 5 6 7 8 9 6 7 8 9 6 7 8 9 w G x i S w Δp Room Key Δp Pressure difference S Contacts closed Damper OPEN up to the set limitation max S Contacts closed Damper CLOSED w Command variable (e.g. temperature controller, sash sensor) w Command variable from room-pressure controller x i Actual value, air volume, command variable for addition unit y A Positioning signal, control action A y B Positioning signal, control action B Damper OPEN up to the set limitation max Damper CLOSED Alternative: Priority control to several controllers Dimension drawing 8 6 09 6 4 09 6 68 S y B y A 4 V~ S Δp V max. V = 0 S A080 4,5 Ø6,8 4 Ø4,7 004 74400 04
4.4/4 RLE 5 Example of use Room-pressure control Due to high demands placed on the level of seal of clean rooms or laboratories, particular attention should be paid to maintaining the pressure in these areas. To do so, only systems with supply-air and return-air VAV controllers should be used. The room pressure in laboratories is normally controlled via the supply air (negative-pressure control), and in clean rooms usually via the return air (positivepressure control). The room pressure is kept constant by cascading room-pressure controllers and VAV controllers. To do this, the command signal of the room-pressure controller (y) is fed to the input (W ) of the VAV controller. The room-pressure controller has an influence of max. +/ 5% on the VAV controller. The value set on the Δ % adjuster therefore acts as the minimum limitation. This system requires no door contacts to freeze the room-pressure control. The control of the room pressure is always effected with respect to a pressure reference (reference pressure source, e.g. accessory 097867 00).. Control facility for variable air volume for closed rooms. Positive or negative pressure is controlled so as to affect the return-air controller. Room pressure can be set on the room-pressure controller. Control action A. V SA geschlossener Raum enclosed room local étanche V EA RLE 5 F00 RLE 5 F00 RLE 50 F00 4 w PD Reference B0464a 74400 04
RLE 5 4.4/5. Control facility for variable air volume with temperature control for closed rooms. Positive or negative pressure is controlled so as to affect the return-air controller. Room pressure can be set on the room-pressure controller. Control action A. aster/slave configuration. V SA LE geschlossener Raum enclosed room local étanche V EA V Valve 9 RLE 5 F00 5 T RLE 5 F00 w P xi RLE 50 F00 4 w PD V ZU V Ventil w, y V FO Reference LE V Fume cupboards In order to safeguard the ability to restrain contaminants in fume cupboards as per EN 475, various solutions are permitted. The difference lies in the way in which the requirement for the air volume is measured: either in proportion to the front sash opening of the fume cupboard or in proportion to the air inlet speed. The air volume must react within seconds in proportion to the amount that the fume cupboard s front sash is opened, i.e. on opening the sash, the actuator s positioning time must be short. This can be achieved only with fast-running damper drives ( 5 sec. for an angle of 90 ). The command signal w for the RLE 5 controller is set by the SGU 00 sash sensor or via the RXE 0 F00 operating unit (in combination with the SVU 00 air-flow sensor). The air volume is adjusted between the set Vmin and Vmax values in accordance with the setpoint. The required reaction times between opening/closing the fume cupboard and the air volume s control loop are shown in the diagram below. T R T R X t T R T R B0465a Control diagram 74400 04
4.4/6 RLE 5. Fume extraction as per EN 475 with acoustic and optical alerting controlled in proportion to the amount that the fume cupboard s front sash is opened. The position of the front sash on the fume cupboard is detected by a sash sensor. The sensor s output signal is fed to the VAV controller as the setpoint. This adjusts the volume of air within seconds in accordance with the position of the front sash. V EA Control diagram Volume flow Sequence: Fume Hood SGU 00 F00 6 G 00% EA RLE 5 F00 EY 0% 7 0% 0% 50% 00% closed sash position open RXE 0 F00 B0466 4. Fume extraction as per EN 475 with acoustic and optical alerting, controlled in proportion to the flow speed. The inlet speed of air into the fume cupboard is measured by an air-flow sensor. By varying the air volume, it is possible to maintain a constant air inlet speed at a value equivalent to the (variable) setpoint, e.g. 0,4 m/s. Any deviations from this are reported by the operating unit whenever the alarm limits are exceeded. V EA Control diagram SVU 00 F004 6 V Volume flow 00% Sequence: Fume Hood Face velocity EA m s Alarm EY RLE 5 F00 7 0% 0% 0% 50% 00% closed sash position open 0,4 Alarm 0,0 RXE 0 F00 B0467 74400 04
RLE 5 4.4/7 5. Electronic laboratory control system with air balancing by measuring the total air volume. The volume of air to be extracted from the laboratory is ascertained by measuring the air volume in the common return-air duct and fed to the return-air/supply-air VAV controller as the command variable. Using a room-temperature sensor with setpoint adjuster, the volume of air can be raised from min to max. The required negative room pressure is set on the return-air controller by means of the Δ offset. As a matter of priority, the return-air controller is closed and, in a second step, if the total amount of return air is excessive, the supply air is increased. Generally speaking, any number of fume cupboards with autonomous control can be installed in the laboratory. geschlossener Raum enclosed room local étanche xi RLE 5 F00 8 8 w RLE 50 F00 4 RLE 5 F00 PD RLE 5 F00 SGU 00 F00 6 G 9 T P y EY w 7 RXE 0 F00 B0468 Control diagram Total Exhaust Air Supply Air Fume Hoods volume flow Opening of Fume Hoods Exhaust Air Constant Exhaust Air B050 74400 04
4.4/8 RLE 5 6. Electronic laboratory return-air/supply-air VAV control system. All the flows of return air leaving the laboratory are measured for their actual values and fed to a laboratory controller for balancing out the room air. This calculates the requirement for both the supply air and the return air so that the minimum throughput of air in the laboratory is not undercut. On raising the air volume across the fume cupboards by opening the front sash, the amount of supply air is increased. In sealed rooms, a room-pressure controller can also be connected to the supply air so that the room pressure remains stable within given tolerances. The number of fume cupboards or specialist extraction systems in the room is theoretically unlimited. RLE 5 F00 geschlossener Raum enclosed room local étanche 8 8 w RLE 50 F00 4 0 5 xi SGU 00 F00 6 G RLE 5 F00 RLE 5 F00 EY 9 T Limit V 7 P RXE 0 F00 w B0469 7. VAV control affecting the frequency converter directly. 50 Hz RLE 5 Y B FC min 0 Hz B05a VAV controller 8 anual damper Damper drive, 6 s 90 9 Room-temperature controller Reduction unit 0 Addition unit, analogue/ddc 4 Room-pressure controller Frequency converter 5 Actuators Ventilator 6 Sash sensor EY Control centre, night mode, collective alarm 7 onitoring unit *) If the maximum permissible volume of return air is exceeded due to there being too many fume cupboards open, it is possible to reduce the volume of air at the opened fume cupboards by using a variable simultaneity factor ( limit). At the same time, an acoustic alarm is triggered on the operating unit 7. Printed in Switzerland Right of amendment reserved N.B.: A comma between cardinal numbers denotes a decimal point Fr. Sauter AG, CH-406 Basle 74400 04