TN2900/TN3900 Series Mass Flow Controllers and Meters

Transcription

1 TN2900/TN3900 Series Mass Flow Controllers and Meters User Guide Celerity, Inc. 915 Enterprise Boulevard Allen, TX USA T F A REV /07

2 CONTENTS _1.0 SYSTEM DESCRIPTION 1 _1.1 MODELS 1 _1.1.1 MASS FLOW CONTROLLERS 1 _1.1.2 MASS FLOW METERS 1 _1.2 COMPONENTS 2 _1.3 FLOW SENSOR 2 _1.4 BYPASS (FLOW-SPLITTER) 3 _1.5 SLOTTED-DISC BYPASS (TN290X/TN291X SERIES ONLY) 3 _1.6 CYLINDRICAL SCREEN BYPASS (TN292X SERIES ONLY) 4 _1.7 CONTROL VALVE 5 _1.8 SOLENOID VALVES (TN290/TN291/TN2920 SERIES ONLY) 5 _1.9 PILOT CONTROL SOLENOID VALVE (TN2925 SERIES ONLY) 5 _1.10 ELECTRONICS 6 _1.11 COVER 7 _1.12 SPECIFICATIONS, ELASTOMER SEALED MODELS 7 _1.13 SPECIFICATIONS, METAL-SEALED MODELS 8 _2.0 INSTALLATION 10 _2.0.1 ISOLATION/SHUT-OFF VALVES 10 _2.0.2 TUBING CLEANLINESS 10 _2.0.3 IN-LINE FILTER/PURIFIER 10 _2.0.4 FITTINGS 10 _3.0 OPERATION 15 _3.1 START-UP 15 _3.2 OPERATING MODES 15 _3.3 USE IN VACUUM SYSTEMS: 15 _3.4 NORMALLY-CLOSED VALVES: 15 _3.5 SAFETY FEATURES AND PRECAUTIONS 15 _3.6 MANUAL OVERRIDES 16 _4.0 MAINTENANCE 17 _4.1 PERIODIC TESTING/CALIBRATION 17 _4.2 CLEANING 17 _4.3 DISASSEMBLY PROCEDURE: 17 _4.4 CLEANING PROCEDURE 17 _4.5 RE-ASSEMBLY PROCEDURE: 18 p. i

3 CONTENTS _4.6 ADJUSTMENT AND CALIBRATION PROCEDURES 18 _4.7 CALIBRATION PROCEDURE - INDICATED VERSUS ACTUAL FLOW 19 _4.8 VALVE ADJUSTMENT (MFCS ONLY) 19 _4.9 TN2900 SERIES ONLY: 19 _4.10 DYNAMIC RESPONSE ADJUSTMENT (MFCS ONLY): 20 _TN2920 Series: 20 _4.11 BYPASS ADJUSTMENT 21 _TN2920 Series ONLY 21 _4.12 TN2900 AND TN2936 BYPASS ADJUSTMENT 22 _4.13 RANGE CHANGE 22 _4.14 MAINTENANCE TOOLS 22 _5.0 TROUBLESHOOTING 23 _5.1 INITIAL TEST 23 _5.2 TROUBLESHOOTING CHARTS 23 _5.3 SENSOR REPLACEMENT 25 _5.4 SOLENOID VALVE REPLACEMENT 25 _5.5 DRAWINGS 25 _APPENDIX A - PARTS AND EQUIPMENT 34 _Spare Parts 34 _Additional Equipment 34 _APPENDIX B - SERVICE AND RETURN 35 _Service Instructions 35 _Return Instructions 35 _APPENDIX C - TN2920 VALVE ADJUSTMENT 37 _TN2925 Valve Adjustment 37 _6.0 WARRANTY 39 p. ii

4 _DESCRIPTION SYSTEM DESCRIPTION 1.1 MODELS This manual (replacement for manual numbers , , , , and ) provides installation, operation, maintenance, and troubleshooting information for the following devices, as these devices are similar in function, and vary only in size (flow rate), seals, and control valve type (Ranges are N 2 equivalent) Mass Flow Controllers Connection Flow Range Seals Model Control Valve Card Edge 15-Pin "D" 9-Pin "D" 10 sccm - 10 slpm Elastomer TN sccm - 30 slpm Metal TN2900M Normally-open or normallyclosed solenoid 100 sccm - 30 TN2910 slpm slpm TN2920 Normally-closed solenoid Elastomer slpm TN sccm - 10 slpm Elastomer TN2901 Utilizes a solenoid valve as a pilot to control a process gasactuated 350 stainless steel bellows valve to provide accurate control at high flow rates 10 sccm - 30 slpm Metal TN2901M Normally-open or normallyclosed solenoid 100 sccm - 30 TN2911 slpm slpm Elastomer TN2921 Normally-closed solenoid slpm TN2926 (See TN2925) 10 sccm - 10 slpm Elastomer TN2902 Normally-open or normallyclosed solenoid 10 sccm - 30 slpm Metal TN2902M 100 sccm - 30 Normally-open or normallyclosed solenoid TN2912 slpm slpm Elastomer TN2927 (See TN2925) slpm TN2922 Normally-closed solenoid Mass Flow Meters Connection Flow Range Seals Model Card Edge 15-Pin "D" 9-Pin "D" 10 sccm - 10 slpm Elastomer TN sccm - 30 slpm Metal TN3900M 100 sccm - 30 slpm TN slpm Elastomer TN slpm TN sccm - 10 slpm Elastomer TN sccm - 30 slpm Metal TN3901M 100 sccm - 30 slpm TN slpm Elastomer TN slpm TN sccm - 10 slpm Elastomer TN sccm - 30 slpm Metal TN3902M 100 sccm - 30 slpm Elastomer TN slpm TN3927 Elastomer slpm TN3922 p.1

5 _DESCRIPTION COMPONENTS Celerity flow controllers and flow meters accurately and reliably measure and control the mass flow rate of gases. They have been specifically designed to allow operation on any gas having a known molar specific heat (Cp). The mass flow controllers each consist of a closed-loop control system which measures the mass rate of gaseous flow through the instrument, and adjusts a flow control valve as needed to control flow to the commanded level. Each flow controller consists of four basic elements: Flow sensor Bypass (flow-splitter) Control Valve Electronics which condition the flow signal and drive the control valve 1.3 FLOW SENSOR The flow sensor consists of two self-heated resistance thermometers wound around the outside diameter of a thin-walled capillary tube. These coils, each having a resistance of 330 ±13 ohms at 24 C, are connected in a bridge circuit and supplied with a regulated current. The heat generated by the power dissipated in the coils raises the tube temperature approximately 70 C above ambient. At no flow, this heat is symmetrically distributed along the tube. With gas flowing in the sensor tube, heat is carried downstream. The resulting shift in temperature makes the upstream sensor cooler than the downstream sensor. This temperature difference (and corresponding electrical resistance difference) is directly proportional to the mass flow rate of the gas through the tube. The bridge output, being a direct function of the resistance difference, is amplified and further linearized by the electronics to give a 0 to 5.0 VDC indication of flow rate. Increasing the flow rate well above the full-scale range of the instrument will eventually cool the entire sensor tube and the output signal will reverse and asymptotically approach zero. The capillary tube is dimensioned to have a minimal mass (for fast response) and an extremely large length-to-diameter ratio to ensure laminar flow over the full operating range. The housing which encases the sensor tube is precisely configured to minimize both external and internal natural convection currents from one coil to the other, thus allowing the instrument to be mounted in any position with no zero adjustment required to re-establish the original calibration. This configuration minimizes the mass of the sensor resulting in a time constant that is one-third that of other sensors of similar p.2

6 _DESCRIPTION 1.0. Figure 1: Typical Flow Sensor design. Overall flow controller response can therefore be dynamically controlled to eliminate overshoot. 1.4 BYPASS (FLOW-SPLITTER) The bypass, which is located in the primary flow path in the base assembly, produces a linear pressure drop versus flow rate between the inlet and outlet of the sensor tube, which in turn produces a 0 to 100% sensor flow for 0 to 100% flow of the instrument. In order to ensure a constant ratio between sensor flow and total flow (independent of pressure, temperature, and gas properties), the bypass arrangement has been designed to maintain the flow well within the laminar region of fluid flow over the entire range of the instrument. 1.5 SLOTTED-DISC BYPASS (TN290X/TN291X SERIES ONLY) The bypass consists of a stack of slotted discs held in place by a bypass nut. Gas flows through the nut and is directed to the outer diameter of the discs where it flows radially through the slots and exits through the opening between the inner diameter of the discs and the triangular extension of the nut. The slots have a sufficient length to diameter ratio to maintain laminar flow over the operating range of the sensor, thereby providing the constant and independent flow split. By varying the slot depth, the number of slots per disc, and the number of discs per assembly, the bypass can be adjusted to provide the required full scale pressure drop of the sensor coincident with the desired full scale range of the flowmeter. Bypass assemblies are factory-built to specific ranges with the discs held in place by a removable washer made of Teflon fluoropolymer. p.3

7 _DESCRIPTION 1.0 Figure 2: Slotted-disk Bypass 1.6 CYLINDRICAL SCREEN BYPASS (TN292X SERIES ONLY) The cylindrical screen bypass has an adjustable plug inside a fine-mesh screen that determines how much screen is available for gas to flow through. If the plug is adjusted fully to the out position, maximum gas flow is allowed. The holes in the screen have a sufficient length to diameter ratio to maintain laminar flow over the operating range of the sensor, thereby providing the constant and independent flow split. The flow range is factory set by adjusting the position and size of the stainless steel bypass. Only the TN2920 has an adjustment screw that is used for factory adjustments. The TN2925 By-Pass is non adjustable as shown in Figure 4. Figure 3: Cylindrical Screen Bypass p.4

8 _DESCRIPTION 1.0 Figure 4: TN2925 By-Pass 1.7 CONTROL VALVE Each MFC and flowmeter uses a control valve that is optimized for its flow range, control stability, and response to setpoint. Table 1: Model Control Valve Types Models Flow Rate Control Valve Shutoff Capability TN290x/TN390x 10 sccm to 10 slpm Normally-closed or Normally-closed: <2% TN291x 10 slpm to 30 slpm normally-open solenoid full scale Normallyopen: <4% full scale valve. TN slpm to 200 slpm Normally-closed solenoid valve. <4% of full flow Normally-closed pilotoperated solenoid valve to TN2925/26/27 up to 1000 slpm control a process gasactuated 350 stainless steel <5% of full flow. (<10% for H bellow valve to provide 2 and He) accurate control at high flow rates. 1.8 SOLENOID VALVES (TN290/TN291/TN2920 SERIES ONLY) The valve is designed to provide a relatively constant control range (stroke) over the entire flow range. Different ranges within the full range of a particular valve seat are accommodated by the amount of voltage applied to the valve and an air-gap adjustment which varies the force versus stroke characteristic. This arrangement provides consistent dynamic response and static stability with only a minimal need for electronic tuning. 1.9 PILOT CONTROL SOLENOID VALVE (TN2925 SERIES ONLY) The control mechanism in the TN2925 series is a pressure-operated bellows valve which is piloted by a normally- closed solenoid valve. The pneumatic amplification provides large orifice area modulation without the high power and force normally required by conventional valve actuating techniques. With the pilot valve closed, the bellows valve is pressure-balanced against its orifice with the closing force determined by the pre-load of the bellows. This preload is set by adjusting the position of the bellows assembly within the bore of the base. As voltage is applied to the proportional solenoid control valve, it opens and increases flow through the inlet bellows. The resulting pressure differential across the valve orifice drives the valve open in proportion to the increasing flow through the pilot valve. Large strokes against the large orifice are thereby achieved with very small flows through the control valve. Ratios of total flow to p.5

9 _DESCRIPTION 1.0 pilot valve flow of 200 or more are easily achieved requiring no more force or power than is necessary for a flow control system having less than 1% of the flow capacity ELECTRONICS The electronics consist of a circuit board with a hybrid Auto-Zero circuit soldered in place. A +5 VDC regulator supplies power to the Auto-Zero circuit and also provides the reference voltage required for the Valve OFF function. A -5 VDC regulator provides the reference for the sensor bridge, constant current source, and the linearization circuit. Table 2: Electronics Connection Current Source Flowmeter Amplifier Circuit Linearity Circuit Auto-Zero Circuit (MFCs only) Description Delivers a constant 12.7 ma to the sensor bridge which floats between the plus and minus supplies. This arrangement gives extremely high common-mode rejection and allows insensitive operation over a wide range of supply voltage levels. The Sensor Bridge circuit contains the zero and span temperature compensation networks. Amplifies the sensor output signal. This circuit also incorporates a speedup filter which provides for matching the sensor response to the actual flow rate response during a transient flow condition. Provides a variable gain versus input voltage allowing correction for any non-linearity of the sensor output signal. Provides periodic correction of zero offset due to long-term sensor drift, temperature and pressure variations, or other environmental causes. This feature ensures long-term calibration accuracy and eliminates the need for periodic manual zero adjustment. The range of correction is limited to ±2.5% of full scale to prevent erroneous correction of an undetectable leak or defective sensor. The Auto-Zero function is activated either by commanding 1% of full scale flow rate which automatically closes the control valve or connecting Pin L to common. After a 80 to 100 second delay, the output signal is compared with (and driven to) zero within 2.5 seconds. This correction is maintained until the next update. The current or latest correction can be permanently stored in memory by an external command such that in the event of power loss, the output will return to zero when power is re-applied. (Automatic on D connectors. Compares the flowmeter output signal with the command voltage (setpoint) and varies the voltage to the valve to throttle the flow to the commanded level via closed loop control. The ramp circuit limits the rate of change of the setpoint allowing the sensor output to keep-up, thus minimizing overshoot during step changes in commanded flow rate. If a slower response is desired, jumper JP1 can be removed to give a 10-15% per second rate of change to the desired flow rate. Valve Control Circuit Balanced Power Load Circuit While the integral and derivative functions of the PID control circuit are relatively fixed, the proportional band (gain) of the circuit is adjusted by the ratio of R52 to R50. The values of these resistors are selected during dynamic response testing to optimize the transient response of the control loop, and vary depending on the range, gas, and intended operating conditions of the instrument. For Card Edge only: The control logic can be overridden externally to either open or close the valve in accordance with specific process requirements. Note: While connecting Pin D to common may partially open the valve, connecting Pin D to +15 VDC will drive the valve to the full purge position. Limits the current in the common line to a maximum of ±5 ma. This limits the control error to <0.2% per 100 feet of interconnect cable between the flow controller and its setpoint/readout control system. p.6

10 _DESCRIPTION COVER The cover is made of steel and is grounded to the flow base and the chassis ground connection. This, in conjunction with the roll-off and filter capacitors in the electronics, provides excellent EMI protection SPECIFICATIONS, ELASTOMER SEALED MODELS Table 3: Specifications, Elastomer Sealed Models Performance Flow Rate Turndown Ratio Attitude Sensitivity Step Response Time (dependent on step request and conditions) TN2900 Series TN2920 Series TN2925 Series TN2900: 10 sccm - 10 slpm TN2910: 100 sccm - 30 slpm (TN2910 used below 10 slpm for low vapor pressure material delivery) Normally-closed: 50:1 normally-open: 20: slpm 200 to 1000 slpm 25:1 20:1 (10:1 on H 2 and He) <0.25% Full 90 (without auto-zero) 1 sec slpm: 3 sec slpm: 6 sec 5 sec Accuracy ±1.0% full scale ±2.0% full scale ±2.0% full scale up to 300 slpm ±3.0% full scale up to 1000 slpm Linearity ±0.5% full scale ±1.0% full scale Repeatability ±0.2% full scale ±0.5% full scale Temperature Coefficient 0.05% per C for zero and span 0.01% per C for zero and span Pressure Coefficient % per bar, 0.007% per psi (typical) Electrical Supply Voltage + & -15 VDC nominal ±20% Power Supply Sensitivity <0.01% per volt Supply Current Power Power Consumption Input/Output Signal Input Impedance Minimum Load Impedance Mechanical Control Valve Type Materials Exposed to Process Gas Elastomers Available Leak Integrity 110 ma nominal (125 ma max + & -18 VDC) & -15 VDC 0-5 VDC (Optional TN2901/02: 4-20 ma DC) 500K ohms (minimum) (Optional TN2901/02: 250 ohms) 2000 ohms (Optional TN2901/02: 250 ohms) Normally-open or normallyclosed solenoid 316L stainless steel, 446 stainless steel, PFA Teflon fluoropolymer ±170 ma max. (200 ma max + & -18 VDC) FM: ± 35 ma max. (45 ma max + & -12 VDC) & -15 VDC FM: 1 + & - 12 VDC 0-5 VDC (Optional TN2921: 4-20 ma DC) 500K ohms (minimum) (Optional TN2921: 250 ohms) 2000 ohms (Optional TN2921: 250 ohms) Normally-closed solenoid 316L stainless steel, 420 stainless steel, PFA Teflon fluoropolymer 110 ma TN3925/2926: 35 ma 0-5 VDC (Optional TN2926: 4-20 ma DC) 500K ohms (minimum) (Optional TN2926: 250 ohms) 2000 ohms (Optional TN2926: 250 ohms) Solenoid pilot valve (NC) to control a process gas-activated bellows valve 316L stainless steel, 446 stainless steel, AM-350 SS Viton, Neoprene, or Kalrez Viton or Kalrez 1 x 10-9 atm-cc per sec (He) inboard 1 x 10-9 atm-cc per sec (He) inboard 1 x 10-9 atm-cc per sec (He) inboard p.7

11 _DESCRIPTION 1.0 Valve Leakthrough Normal-closed: <2% full scale with Teflon fluoropolymer poppet Normally-open: <5% full scale with Teflon fluoropolymer poppet <4% full scale Surface Finish Internal 0.83 µm (32 µin Ra) Weight 0.9 kg (2 lbs) 2.0 kg (5.0 lbs) 2.5 kg (5.5 lbs) Environmental Process/ Environmental Temperature Range 0-50 C ( F) (ambient and gas) Humidity 0-95% Relative Humidity, non-condensing Maximum Inlet Pressure Minimum Inlet Pressure Maximum Differential Pressure Minimum Environmental Pressure Table 3: (Continued) Specifications, Elastomer Sealed Models TN2900 Series TN2920 Series TN2925 Series 10.3 bar (150 psig) 10.3 bar (150 psig) proof: 34.5 bar (500 psig) TN3920: 34.5 bar (500 psig) proof: bar (500 psig) 10.3 bar (150 psig) proof: 34.5 bar (500 psig) TN3925/3926: 34.5 bar (500 psig) proof: bar (500 psig) 175 kpa (10 psig) 100 Torr 10 sccm to 10 slpm: kpa (10-40 psid) slpm: kpa (15-40 psid) slpm: kpa (20-50 psid) slpm: kpa (30-60 psid) slpm: kpa (40-60 psid) TN3920: 5 psid max >100 Torr (2 psia) slpm: kpa (30-60 psid) slpm: kpa (40-80 psid) slpm: kpa (50-80 psid) TN3925/3926: 5 psid max 1.13 SPECIFICATIONS, METAL-SEALED MODELS Table 4: Specifications, Metal Sealed Models TN2900M TN2930M TN2936MEP/TN2936MEP Performance Flow Rate 10 sccm - 30 slpm Turndown Ratio 50:1 Step Response Time (dependent on step request and 500 msec conditions) Accuracy ±1.0% full scale Linearity ±0.5% full scale Repeatability ±0.2% full scale Reproducibility ±0.3% full scale/10 weeks Attitude Sensitivity <0.25% Full 90 (without auto-zero) Temperature Coefficient 0.05% per C for zero and span Pressure Coefficient % per bar, 0.007% per psi (typical) Delay Time: 80 ±20 sec Auto-Zero Option Correction Time: <2.5 sec Resolution: 0.1% of full scale Range: ±2.5% of full scale Electrical Supply Voltage + & -15 VDC nominal ±20% p.8

12 _DESCRIPTION 1.0 Power Supply Sensitivity Supply Current Power Table 4: (Continued) Specifications, Metal Sealed Models TN2900M TN2930M TN2936MEP/TN2936MEP <0.01% per volt 110 ma nominal, (Optional: 130 ma nominal, 150 ma 18 VDC) Power Consumption & -15 VDC 0-5 VDC Input/Output Signal (Optional: 4-20 ma DC) Input Impedance Minimum Load Impedance Mechanical Control Valve Type Materials Exposed to Process Gas Leak Integrity Valve Leak-through Surface Finish Internal Connections Inlet/Outlet, Mechanical Environmental Operating Temperature Range Humidity Maximum Inlet Pressure Maximum Outlet Pressure Maximum Differential Pressure Minimum Environmental Pressure Warranty Normally-closed solenoid 1/4 VCR 1/4" buttweld 500K ohms (minimum) 2000 ohms (Optional: 250 ohms) Normally-open or normally-closed solenoid 316L SS, 321 SS 446 SS, Nickel 200, Ruby, TA Ceramic 1 x atm-cc per sec (He) inboard <2% full scale 0.4 Ra, avg (non EP) EP: 0.25 µra, max (EP) 1/4 VCR 0-50 C (ambient and gas) 0-95% Relative Humidity, non-condensing 10.3 bar (150 psig) 10 sccm to 10 slpm: kpa (10-40 psid) slpm: kpa (15-40 psid) >100 Torr (2 psia) 1 year or 100,000 cycles p.9

13 _INSTALLATION 2.0! WARNING! LEAK HAZARD. Protect the fittings! Fitting caps should not be removed from the instrument until installation. Scratches and dents on the fittings will cause the systems to leak. 2.0 INSTALLATION 1. Install the MFC or Flowmeter in a proper plumbing configuration Isolation/Shut-off Valves An MFC is NOT a positive shut-off device. When commanded closed, an MFC will allow a small flow through the device. You should install two isolation/shut-off valves with EACH MFC to ensure positive shut-off and to protect the MFC: install one shut-off valve upstream to eliminate flow surge during turn-on and one shutoff valve downstream to prevent back migration of contaminants into the MFC. These shutoff valves will also allow you the ability to more easily conduct inplace testing of the MFC with verifiable zero flow Tubing Cleanliness Tubing should be pre-cleaned and polished to eliminate particulate contamination and ensure leak-tight operation In-line Filter/Purifier An in-line filter or purifier should be installed just upstream of the MFC to prevent the possibility of any foreign material entering the flow sensor or internal control valve. Be sure to size the filter for the proper flow rate and pressure drop rating as needed for your gas line. Depending on your gas type and process, a purifier may be desired. Consult a Celerity Gas Applications Specialist for your application Fittings Gasket Seal (fittings compatible VCR connection): Always use a new metal gasket each time you make-up the fitting. Never reuse gaskets as they will leak. Verify that you are using a gasket that is compatible with your gas type, then tighten the gasket seal fittings 1/8 turn past hand-tight for 3/8" and larger fittings, or a maximum of 1/4 turn past hand-tight for 1/4" fittings. DO NOT overtighten. Refer to fitting manufacturer s instructions for details for your fitting material and size. Compression Seal (fittings compatible with Swagelok connections): Tighten compression seal fittings per manufacturer s instructions. Typically 1 1/4 turn past hand-tight to initially make-up the fitting. Then 1/4 turn past hand-tight to re-tighten previously made-up fittings. Use the manufacturer s inspection gauge to ensure that the fitting is properly tightened. 2. Ensure a proper operating environment CLEANLINESS: For maximum performance and service life, the instrument should be installed in a clean, dry atmosphere, relatively free of shock and vibration. ACCESS: Ensure that there is sufficient room for access to the electronics and plumbing to facilitate maintenance and removal for cleaning. RF ISOLATION: Avoid installation of the instrument in close proximity to high sources of RF noise and/or mechanical vibration. If this is unavoidable, proven methods of instrumentation filtering, cable shielding, and/or shock mounting should be utilized. p.10

14 _INSTALLATION 2.0! CAUTION! Proper differential pressure from the inlet pressure to the outlet is critical to the correct operation of the device. Too high or too low of a differential pressure can cause the device to oscillate or provide incorrect outputs. TEMPERATURE: The instrument may be operated at any temperature from 0 to 50 C, provided the gas and ambient temperatures are maintained equally. Since the indicated flow rate has a temperature coefficient of ±0.05% per C. You may want to calibrate the instrument at the actual operating temperature to maximize the measurement accuracy. Contact your Celerity Applications Specialist for details. PRESSURE: Flow controllers may be operated at any gas pressure up to 1135 kpa (150 psig or 10.3 bar). Since the indicated flow rate varies in direct proportion to specific heat (Cp), which varies differently with pressure and temperature depending upon the molecular structure of the gas, it is recommended that the instrument be calibrated at the actual operating pressure. NOTE: The pressure coefficient of ±0.001% per kpa (±0.007% per psi) generally applies to monatomic and diatomic gases only. 3. Mounting Refer to the dimensional drawings. Two (8-32 UNC or UNC) tapped holes are provided for mounting. 4. Connect the electronics Refer to the appropriate electrical hookup diagram on page 12 or 13. Table 5: Electronics Connection Power Control Signal Output Indication Valve OFF Valve Test (Override) Description Any + & -15 VDC power supply meeting the requirements as designated in the specifications may be used to energize the instrument. Any 0 to 5.0 VDC command voltage having a source impedance of 2500 ohms or less may be used. The input impedance of the flow controller is 0.5M ohm (minimum). (4-20 ma current option is available on selected models) Any 0 to VDC meter with at least 1000 ohms/volt can be used to provide visual indication of the mass flow rate. Recorders, voltage dividers (for conversion to engineering units), and other instrumentation may be added, provided the total load impedance is no less than 2000 ohms. The source impedance of the flowmeter output signal is less than 0.5 ohm. (4-20 ma current option is available on selected models) A TTL low signal will override the control signal, close the valve and trigger the Auto-Zero function. TTL high (or open connection) allows normal control operation. (Not available on 9-Pin "D" models.) The valve voltage may be monitored during normal operation using a high input impedance DVM. Connecting this pin to common or the +15 VDC supply will override the control signal and open the valve. A maximum current of 75 ma is required for the TN2900 and TN2925 Series, 125 ma for the TN2920 Series. The internal negative reference voltage (-5 VDC) may be Zener Test monitored for troubleshooting purposes using a high impedance DVM (+5 VDC on the subminiature "D" connector version). Following for Card-Edge Only: Auto-Zero Inhibit Auto-Zero Store Auto-Zero Trigger The Auto-Zero function may be inhibited (deactivated) by applying a TTL low signal. This pin may also be used as an output, as it goes high during the 2.5 second adjustment cycle. Momentary application of a TTL low signal stores the latest zero correction in memory. This is automatically recalled on power up (Automatic on TN2901/02). The Auto-Zero function may be triggered by applying a TTL low signal to Pin L. This will override the setpoint signal and close the valve. Note: Shorting to common may be substituted for TTL low, and open connections substituted for TTL high. p.11

15 _INSTALLATION 2.0 AZ Store 1 AZ Inhibit 1 Valve Test (Over Ride) Zener Test Point (-5.0 VDC) Valve OFF Chassis Ground +15 VDC Supply Common -15 VDC Supply 0-5 VDC + Output Signal - TTL High = Control Mode TTL Low = Closed (Auto-Zero Trigger) Store 1 Inhibit 1 Active 1 Open Control Mode Purge 0-5 VDC - Command Signal VDC Ref Solenoid Supply Voltage --- A B 2 3 F C 4 1 L 6 D J K Card Edge pin D 2 AB CD E 5 F 6 J 8 K L N.C. Series Shut-off Valve FLOW (optional) Notes: 1 Auto-Zero (AZ) circuit is not available on TN2900B, TN2910B, and flow meters. AZ Store is internally automatic on TN2901, TN2911, and TN2901M and TN The following is optional by request on TN2901, TN2911, TN2901M, TN2926 TN3901, TN3911, TN3901M, and TN3926 only: Pin-7, 4-20 ma In (MFC only); Pin-4, 4-20 ma Out. Figure 5: Card Edge and 15 Pin D Electrical Hookup Diagram p.12

16 _INSTALLATION 2.0 Figure 6: 9 Pin D Electrical Hookup Diagram DANGER LEAK HAZARD. CRITICAL: You must leak check all system fittings prior to use. Failure to leak-check the system with proper helium leak-checking techniques could compromise the integrity of the system, the process, your equipment, and could endanger personnel. 5. Test the cables Test the interconnect cable for continuity, pin-to-pin shorts, and correct pin assignments per the electrical hook-up diagram. 6. Leak-Check the System NOTE: After installation of the instrument and prior to its use, the gas delivery system should be thoroughly leak tested and purged prior to use. (Recommended level for elastomeric seals is l x l0-9 atm cc/sec of helium, or less.) If the MFC is equipped with a normally-closed control valve, you MUST command the valve to the open position to purge the MFC. With a + & -15 VDC power supply, apply 5 VDC (full flow setpoint), or connect the Valve Test point to +15 VDC. 7. Purge the gas lines Apply + & -15 VDC power and allow a 30 minute warm-up time before pressurizing the system with PURGE gas. Fully-open the MFC or flowmeter and perform a cycle purge of the gas system. NOTE: A cycle purging technique is more effective in removing atmospheric contaminants than a simple continuous purge gas flow. To cycle purge, alternate the flow of purge gas with a pump-down of the gas system to vacuum for several cycles. If vacuum is not available, reducing the pressure to kpa (0 psig) for several cycles should be adequate. Cycle purging helps remove contaminants from small, blind cavities in the system which constitute a virtual leak source. p.13

17 _INSTALLATION 2.0 NOTE: If the MFC is equipped with a normally-closed control valve, you MUST command the valve to the open position to purge the MFC. With a + & -15 VDC power supply, apply 5 VDC (full flow setpoint), or connect the Valve Test point to +15 VDC.! WARNING! DO NOT convert an elastomer sealed instrument, originally calibrated for a non-reactive, non-corrosive gas to use reactive or corrosive gas unless all the seals are replaced with the suitable compound. Any instrument which has been in reactive or corrosive gas service should be thoroughly purged and cleaned prior to conversion to another gas. Instruments are factory assembled using: - Viton for non-reactives, - Neoprene for Ammonia, - Kalrez for all other reactive and corrosive gases unless specified otherwise. Cycle- Purge the gas system. 8. MFCs - Verify the device flow Apply + & -15 VDC power and allow a 30 minute warm-up time before pressurizing the system with PROCESS gas. If the indicated output does not settle to zero to within 1% full scale (or the level of zero desired), re-zero the instrument (see Adjustment Procedures, page 18) before proceeding. Once the zero has been verified, pressure may be applied. After establishing that no hazardous condition will be created by the venting of process gas, flow controller operation may then be verified over the complete operating range. If the flow output voltage is within 10 millivolts of the setpoint, the flow controller is controlling properly. Check for this condition at the highest and lowest flows anticipated at both the highest and lowest input-output pressure differentials anticipated. Every effort has been made in the design of the instrument to provide safe, trouble-free operation. Key features include reverse power supply polarity protection, output over-voltage and short circuit protection, low component temperatures, and conformance to intrinsic-safety design criteria. Additionally, a built-in threshold circuit ensures that the valve is commanded open at zero command independent of any existing output offset, the valve automatically opens with power failure. For the operator s convenience during start-up, abnormal, or fault conditions the valve command circuit can be overridden externally to drive the valve fully closed. Connecting signal Ev to common will override the control signal and close the valve. Re-adjustment of the valve after purging or repair is described in the Adjustment Procedures, page Calibration Each instrument is factory calibrated for the specific flow range and gas indicated on the nameplate. Standard factory calibration is within ±2.0% and is referenced to standard temperature and pressure. The calibration for other gases can be approximated to ±6% using the Conversion Factor Charts available from Celerity web site. Factory calibration utilizes the test gases detailed in the charts. Calibration checks with other gases can show discrepancies of up to ±6%. Precision calibration equipment is required to obtain calibration accuracy of ±2% after range change or for other gases. Range changes can be made to within ±10% by removing the inlet fitting and adjusting (or replacing) the bypass. Fine tuning to the desired accuracy level can then be accomplished by adjusting the potentiometers on the printed circuit board in conjunction with a reference flow standard, as detailed in the Adjustment and Calibration Procedures available from the Celerity web site "www. Celerity.net" NOTE: In accordance with Semiconductor Equipment and Materials Institute Standard E12-91, Standard Pressure and Temperature are defined as kpa (760mm Hg) and 0 C respectively. p.14

18 _OPERATION OPERATION 3.1 START-UP 1. Apply + & -15 VDC power and allow the instrument to warm-up for 30 minutes before pressurizing the system with process gas. 2. If the indicated output does not settle to zero or within ±1% full scale (or the level of zero desired): re-zero the instrument (see Adjustment Procedures,page 18) before proceeding. 3. Once the zero has been verified, pressure may be applied. After establishing that no hazardous condition will be created by the venting of process gas, flow controller operation may then be verified over the complete operating range. If the flow output voltage is within 10 millivolts of the setpoint, the flow controller is controlling properly. Check for this condition at the highest and lowest flows anticipated at both the highest and lowest input-output pressure differentials anticipated. 3.2 OPERATING MODES In general, the instruments may be operated at any pressure and temperature that falls within the limits stated in the specification. Optimum performance, however, can be achieved and will prevail if the operating pressure and temperature are pre-determined and controlled to a narrow range. Calibrating and fine-tuning the instrument at the actual operating pressure, temperature, and flow rates can significantly improve the performance characteristics. The instruments are factory calibrated at an ambient temperature of 23 C (±3 C) and the inlet pressure set to the midpoint of the operating pressure range and corrected to standard conditions. Flow controllers are adjusted to pass full rated flow at the minimum inlet pressure, with kpa (0 psig) outlet pressure and shut down to less than 2% (TN2900 Series) or 4% (TN2920 and TN2925 Series) of full scale at the maximum inlet pressure. Response time is verified at both extremes. 3.3 USE IN VACUUM SYSTEMS: In vacuum systems, flow controllers maintain their calibration accuracy due to the pressure drop of the control valve downstream of the flow sensing section. The increased pressure drop of the valve due to the increased gas velocity reduces the full-scale flow rate and unless there is sufficient inlet pressure available to overcome the increased pressure drop required, increasing the range of the instrument and/or re-adjustment of the valve may be necessary. 3.4 NORMALLY-CLOSED VALVES: For normally closed valves, it is not necessary to provide an external timedelayed soft-start signal provided the command signal is maintained at zero during the OFF mode and is then applied to the instrument at the same time (or after) pressure is applied. Alternately, Pin L connected momentarily to common prior to applying gas pressure also prevents excessive flow transients at turn-on. A slower ramp change may also be selected for vacuum systems which have small volumes and large flow rates or in other applications where a slower ramped change in flow rate is desirable. p.15

19 _OPERATION SAFETY FEATURES AND PRECAUTIONS Every effort has been made in the design of the instrument to provide safe, trouble-free operation. Key features include reverse power supply polarity protection, output over-voltage and short circuit protection, low component temperatures, and conformance to intrinsic-safety design criteria. Additional feature: A built-in threshold circuit ensures that the valve is commanded closed at zero command independent of any existing output offset. Normally-closed valves: automatically closes in the case of a power failure. Normally-open valves: automatically open in the case of a power failure.! WARNING! YOU MUST leak-check the system plumbing with proper leak check equipment after any mechanical adjustment has been performed on the valve.! WARNING! The following precautions should be taken to prevent damage, minimize safety hazards, and maximize performance:! WARNING! NEVER insert or uplug the connecting cable of the control valve leads with power on if there is a possibility that the ambient atposhpere might be explosive. 3.6 MANUAL OVERRIDES Normally-closed valves: To drive the valve open: connect Pin D (card edge) or Pin 12 (15-Pin "D" connector) to 0 VDC or +15 VDC. To drive the valve closed: connect Pin L to 0 VDC. (The input to close the valve provided on Pin L is active low and conforms to TTL Logic levels.) Normally-open valves: To drive the valve closed: connect Pin D (card edge) or Pin 12 (15-Pin "D" connector) to 0 VDC or +15 VDC. To drive the valve open: connect Pin L to 0 VDC. (The input to close the valve provided on Pin L is active low and conforms to TTL Logic levels.) Should there be a need to purge the system during a power failure or instrument malfunction prior to removing the instrument from the system for repair, the valve may be mechanically opened by first removing the instrument cover and then loosening the lower lock nut and turning the housing of the valve one or two turns counterclockwise. Readjustment of the valve after purging or repair is described on page 19Thoroughly leak test the entire system prior to operation (recommended level for elastomer seals is 1 x 10-9 atm cc/sec. of helium or less). Use only clean, moisture-free (dry) gases. Purge only with dry nitrogen (or other inert gas) before and after breaking into the system. Be sure to OPEN a normally-closed valve. DO NOT purge reactive gas systems with inert gases between runs unless it is required by the process. Even dry gases contain some amount of moisture which will result in contamination build-up. ALWAYS command no flow or ground Pin L when the gas supply is shut off. The command signal should be interlocked with a series shutoff valve to prevent unnecessary over-heating of the control valve during shutoff, and excessive flow surges after turn-on. Avoid installation of the instrument in close proximity to high sources of RF noise and/or mechanical vibration. If this is unavoidable, proven methods of instrumentation filtering, cable shielding, and/or shock mounting should be utilized. p.16

20 _MAINTENANCE MAINTENANCE NOTE: The following instructions and procedures are intended for a laboratory bench top environment. Proper equipment and precautions should be used for any other system or environment. 4.1 PERIODIC TESTING/CALIBRATION Celerity recommends that you return the MFC to a Celerity Service Center for cleaning and calibration at least once each year, or as directed by local procedures to ensure optimum process repeatability and optimum product yields. The optimum (or necessary) service period is dependent on usage, environmental conditions, gas corrosiveness, and related factors, and must be established based upon historical experience in your particular application. 1. Purge the instrument with dry nitrogen for a minimum of 30 minutes prior to removal from the system. 2. Verify the calibration of the flow metering section by comparison with a suitable reference standard or calibrator. 3. Operate the instrument in the control mode over its entire operating range at the minimum and maximum inlet pressures. Check response, stability, and control resolution. 4. Based upon these results, either re-install the device as directed by Celerity technical support or send to the device to Celerity for cleaning and calibration. 4.2 CLEANING Should the instrument show symptoms of internal flow path contamination, it may be disassembled and cleaned. Contamination of the ultra clean surface may cause irreparable damage depending on the severity of contamination.! CAUTION! SHOCK HAZARD. Always make sure power is off before disconnecting or reconnecting the valve to the PC Board.! CAUTION! Do not submerge electronics, sensor or valve coil. Use of harsh solvents, chemicals or HF will likely cause irreparable damage to surface finishes. 4.3 DISASSEMBLY PROCEDURE: 1. Remove power to the device. 2. Remove the screws that secures the cover to the base. 3. Unplug the valve from the PC Board. 4. Remove the screw and standoff that secures the valve to the base and pull the valve assembly out completely. 5. Remove the other standoff that supports the cover. 6. Remove the PC Board from the assembly and, remove the two screws which secure the sensor assembly to the base. 7. Remove the inlet fitting and outlet fittings. 8. To remove the bypass, hold the flow controller in a vertical position (inlet down) and carefully remove the assembly. For slotted-disc devices, note that the discs will be loose. BE CAREFUL not to drop or damage the discs. BE SURE TO NOTE THE ORDER IN WHICH THE DISCS ARE INSTALLED as you will need to replace them in the same order. 4.4 CLEANING PROCEDURE 1. Run a heated ultrasonic cleaner with DI water for a minimum of 5 minutes. Hand clean each part with cleanroom wipes. Reclean using fresh DI water. p.17

21 _MAINTENANCE Dry parts in a vacuum oven for 30 minutes. Maintain and observe cleanroom practices during the cleaning process in preparation for re-assembly. 3. Clean the sensor by running an 0.18 mm (.007 inch) diameter wire (stainless steel or piano) through the full length of the sensor tube 3 or 4 times. If possible, force DI water through the sensor then dry with ultra-pure nitrogen.! CAUTION! You MUST re-calibrate the MFC after replacement or removal for cleaning of the bypass assembly. A calibration shift of as much as 10% may occur during cleaning, depending on the level of contamination.! CAUTION! Factory adjustments should not be altered unless precision gas flow measuring equipment is available for calibration. Rotometers do not have sufficient accuracy for flow measurement calibration unless they have been specifically calibrated and the proper corrections are made for temperature and pressure. 4.5 RE-ASSEMBLY PROCEDURE: Re-assembly should be done in a Class 100 cleanroom environment which includes use of tools and fixtures. 1. Inspect all surfaces under high power magnification for surface degradation. Replace any suspect parts. 2. For slotted-disc devices, the nut and discs should be reassembled in the same order as originally installed (slots upstream, facing shoulder of the nut). Reinstall the bypass and torque to 15 in lb using the bypass adapter on the torch wrench. 3. Install the inlet fitting. 4. Install sensor using new seals. Torque Allen screws 15 in lb. Re-install the PC Board to the sensor with screw and spacer. 5. Install the valve using a new seal and the original centering ring, and torque the Allen screws to 15 in-lb. It will also be necessary to readjust the valve (refer to the Valve Adjustment Procedure). 6. Secure cover support standoffs to the base. 7. Leak check the device to 1 x atm cc/sec Helium. 8. Calibrate the device per the calibration procedure. 9. Re-install the cover. 4.6 ADJUSTMENT AND CALIBRATION PROCEDURES In order to maintain the original factory calibration and performance characteristics of the instrument, the following adjustments may be necessary during routine maintenance and servicing. It is required after any disassembly of the device. 4.7 CALIBRATION PROCEDURE - INDICATED VERSUS ACTUAL FLOW Each controller is factory calibrated for the specific flow and gases indicated on the nameplate. Standard factory calibration is within ±1.0%. The calibration for other gases can be approximated to ±5% by using conversion factors available from Celerity. (See Caution) 1. Thoroughly flush and dry the instrument to remove contaminants (see Cleaning Procedures). 2. Connect a source of gas to the inlet and a suitable flow standard to the outlet. If a volumetric calibrator is used, be sure to apply the proper density corrections to maintain the mass flow calibration. 3. Connect the power and indicator wires (see Electrical Hook-up Diagram) and allow a 30 minute warm-up period. 4. OPEN THE VALVE: Ensure that the valve is open. For normally-closed valves, either mechanically open the valve by turning the valve housing 2 to 3 p.18

22 _MAINTENANCE 4.0 turns counter-clockwise, or electrically drive the valve open. 5. Remove the outlet gas line and cap off the instrument to assure zero flow through the sensor. 6. Adjust ZERO potentiometer RP1 to make the indicator read zero (± 5 mv). 7. Reconnect the outlet gas line and adjust the flow to 40% full-scale value. Set the output to read 2.00 VDC at the full-scale flow rate using the GAIN potentiometer RP2. 8. Recheck zero as described in Step Linearity adjustments are not normally required. After achieving calibration at zero and maximum flow, the full scale calibration may be checked by setting the flow to cause the indicator to read 2.50 VDC. The calibrator should then measure 1/2 of the full range flow rate. If not, set the flow rate to one-half of the full scale value, and adjust the output to 2.50 VDC using the LINEARITY potentiometer RP4. Although this adjustment is essentially independent, steps 5 through 7 should be repeated until all three points are within the desired calibration. 10. The flowmeter section of the flow controllers can be calibrated with the instrument operating in the controller mode and using the setpoint control to dial in the desired flow rate. Adjustments should be made as in steps 5 through 9. When adjusting the gain and linearity potentiometers, the actual flow will change rather than the output voltage since the controller acts to control the output voltage to the commanded setpoint voltage. 11. If the instrument cannot be brought into calibration within the adjustment range of GAIN or LINEARITY, the flowmeter amplifier gain and/or bypass will have to be adjusted. See Range Change on page When using a test gas other than the intended usage gas, a correction factor equaling the ratio of the conversion factors of the two gases must be applied. Contact Celerity for the correction factors. Series TN2900 TN2920 TN2925 Zero Adjust 100% Full Scale (GAIN) 40% Full Scale (LINEARITY) RP1 RP2 RP4 4.8 VALVE ADJUSTMENT (MFCS ONLY) (See page 37 for TN-2920 and TN2925 series valve adjustment) 4.9 TN2900 SERIES ONLY: 1. Remove the cover to permit access to the valve assembly. 2. Connect the inlet of the instrument to a regulated supply of the appropriate gas at the appropriate pressure. Connect a reference flowmeter in series, or monitor the flow as measured by the controller. 3. OPEN THE VALVE: Open the valve, or electrically disconnect for a normallyopen valve. 4. Slowly apply inlet pressure to the controller to 380 kpa (40 psig) or the maximum pressure (see Specifications) and command zero flow. 5. Loosen the lock-nut then SLOWLY turn the adjustment nut clockwise until the flow is reduced to less than 2% of full scale. Cycle the valve from 0% to 100% p.19

23 _MAINTENANCE 4.0! CAUTION! The control valve is not designed for positive shut-off. Do not attempt to adjust closure to less than 1% or the valve may be damaged. then from 100% to 0% full scale to ensure consistent valve closure of less than 2% of full scale. 6. Set the inlet pressure to the minimum expected value and command 100% flow rate. Verify full-scale output. While monitoring the voltage applied to the valve, mechanically fine-tune the valve adjustment to achieve as close to the optimal control voltage as possible. 7. Repeat this process until the valve controls from <2% (See chart below) to 100% full scale at both extremes of pressure. Do not exceed the optimal control voltage. 8. After the valve is properly adjusted and tuned dynamically (see Dynamic Response Adjustment procedure), tighten the lock nut on the top of the valve with 10 to 20 inch-pounds of torque. This will lock the adjusted position in place. 9. Leak check the controller. NOTE: If the valve still exhibits excessive leakage, the seat may be contaminated or damaged. Clean or replace the valve. Before replacing the valve, check the O- ring seal for nicks, cuts, or damage and replace if necessary to ensure an adequate seal between the valve body and the base DYNAMIC RESPONSE ADJUSTMENT (MFCS ONLY): TN2920 Series Series TN290x TN2910/TN2911/TN2912 TN2920/TN2921 TN2925/TN2926 Series Pin to Monitor Card-Edge Pin D to Pin F 15-Pin D Pin 12 to Pin 6 Valve Control TN2900 Series <2% TN2910/TN2911/TN2912 TN2920Series <4% TN2925/TN2926 <5% <10% for H 2 or He Optimal Control Voltage 13 VDC 17 to 20 VDC Each flow controller is dynamically adjusted prior to shipment using a flow measuring device, in series, which is as least 5 times faster than the instrument under test (for experimental details, refer to SEMI Standard E12-91). This verifies that the tuned indicated response is indicative of the actual flow response and does not mask or filter-out overshoot or oscillatory flow conditions. It is recommended that the adjustments not be altered unless suitable equipment is available to adequately display the transient results. If it is found necessary to readjust the response characteristics following cleaning, reassembly, valve adjustment, or range change, the following steps may serve as a guideline. 1. Start with the previously set adjustment, or alternately center potentiometer RP3 and set R50 to 200k ohms. NOTE: A resistance decade box is useful for finding the optimum value for R Supply the instrument with the intended usage gas or a suitable substitute gas at the intended operating conditions including inlet pressure. p.20