AFC 260/AFC 261 - MHz Electronics, Inc
Contents
1. eee 2l 5 3 SENSOR CLEANING AND REPLACEMENT eene tnne tnn 2l 5 4 CONTROL VALVE CLEANING AND REPLACEMENT m 22 SECTION D IROUBLEESHOQOFEINCE ioi Selen a e tuse 23 61 1NITIAE CHECK deem RA 23 6 2 SEVERAL SYMPTOMS acit etate hella exp WEE CO Aa 23 SECTION 7 GENERALMPC PRINCIPLES dtt OH MENU E 26 TA MEM PRINCIPLES get stede eei e 26 7 2 MEASUREMENT PRINCIPLES sjahen 26 SENSORS PRINCIPLES Lionel 27 TA BYPASS PRINCIPLES EE 29 TOGCONTROLE PRINCIPLES sakene 30 SECTION 8 WARRANTY eode nta bo 32 LPRODUCT WARRANTY EE 32 8 2 SERVICES urteon an e Ee 33 SECTION 9 PARTS LISTS AND 0 34 AFC 260 261 User s Manual 4 D 10 017 01 SECTION 1 INTRODUCTION 1 1 SURVEY OF TYPES AND GAS RANGES This user s manual covers the 260 261 models of QUALIFLOW mass flow meters and 360 amp 361 mass flow controllers Gas table and nomenclature are given in Table l Gas Range Mass flow meters Mass flow controllers 0 5000 sccm AFM 360 AFC 260 AFM 361 AFC 261 Table 1 1 Gas Ranges and nomenclature Note The figures related to the gases are with respect to nitrogen For other gases a conversion factor is given in relation to nitrogen 3 4 1 2 SPECIFICATIONS 15VDC 5 25mA 15VDC 5 25mA2. 0 039 1 41 0 185 0 24 0 13 0 5 0 11 0 5 0 122 0 30 D 10 017 01 SECTION 4 ADJUSTMENT PROCEDURE 4 1 REQUIRED FACILITIES To perform any adjustment cleaning or replacement on massflow equipment appropriate tools and facilities must be present as these are high accuracy transducers The facilities are 1 2 3 4 An accurate reference massflowmeasuring system or a flow meter note the pressure and temperature corrections Normal rotameters are not accurate enough The only suffice when relative rough measurements or flow monitoring are necessary A clean room clean tools A voltmeter at least 1000 O V Supply of gas preferably N2 for safe working 4 2 POTENTIOMETERS ADJUSTMENT To gain access to the p c board carefully remove the cover from the body Every flowmeter and controller is calibrated at the factory for a particular gas and flow range as indicated on the top sticker within 1 If any adjustment is necessary a reference measuring system with at least the same accuracy should be used c f 4 1 1 1 To remove containment s the unit must be flushed and dried with nitrogen Apply power to the unit and monitor the output signal Obey a warm up time of about 10 minutes With no flow caps on in and outlet fittings adjust the ZERO potentiometer R3 to give zero output Apply gas to the inlet fitting and put the reference flowmeter in series Disconnect the valve lead wires The valve will fully
3. 01 2 3 3 PRESSURE CONTROL The mass flow controller can be modified to work as a pressure controller Pin 3 is normally connected to pin 10 by jumper J2 see PC board layout in section 4 2 Desoldering this pad disconnects the sensor output signal from the control circuit A pressure transducer output signal 0 5 VDC can now be connected to pin 3 which makes the mass flow controller work as a pressure controller The mass flow can still be monitored through pin 10 2 3 7 RATIO CONTROL For processes that require accurate blending of two or more different gases ratio control can be obtained by a master slave arrangement as shown in figure 2 9 The output signal of the master mass flow controller is used as an input setpoint signal by the slave mass flow controller master AFC setpoint to master AFC Figure 2 9 Ratio control 2 3 4 READ OUT USING A DIGITAL VOLTMETER For testing laboratory or R amp D applications any DC voltmeter or recorder with an impedance of at least 5000 Ohms may be used to monitor the mass flow controller s performance AFC 260 261 User s Manual 13 D 10 017 01 R1 1 kOhm 0 1 voltmeter 1999 mv full scale Figure 2 11 Voltage divider arrangement Full scale 1999 1500 1000 750 600 500 400 300 250 read out mv R2 kOhm 1 50 2 33 4 00 5 67 7 33 9 00 11 50 15 70 19 00 Table 2 Selection of R2 2 5 CHECKS BEFORE START UP Before operating the mass flow controller the following
4. 7 2 1 NTRODU TIN SE 7 2 2 UNPACKING se 7 2 3 MECHANICAL INSTALLATION neess ee 7 2 2 0 GENERXI ee ees 7 2 2 1 INSTALLATI N M 8 2A JBEBCTRIC AL ANS TALE A TION Seen 10 2 3 0 GENERALI ti Uu ete 10 2 351 CONNECTIONS asein M 10 232 SORTS TART COMMAND vcs i 12 2 3 3 el A BERG BC NEE 13 22521 RATIO CONTROL RENNER 13 2 3 4 READ OUT USING DIGITAL VOLTMETER mI 13 22 CHECKS BEFORE STAR BUP SVP ARR QU DM a edad Ics 14 SECTION 3 S OPERA TION te totes senate oe 15 3 1 SENSOR AND BEE eener 15 32 CONTROL VALVE eatis bien ei tit tof t ue eda 15 3o ELECTRONICS estet Sofia MD 15 34 CONVERSION DATA eelere 15 SECTION 4 ADJUSTMENT PROCEDURE ato neos tdeo SEENEN 19 41 REQUIRED FACILITIES su ea Eege 19 42 POTEN HOMETERS ADJUSTMENT re vi eege tege ege DURS 19 TS V ALVEAUDIUSUNIENLD 19 Z4 CHANGE OF CALIBRATION coetu eno clad tea to rto eben oa iu Se 20 4 5 DYNAMIC RESPONSE ADJUSTMENT eerte entere et nnt 20 SECTION S lt MAINTENANCE stus restet eto edi pe UH eS 2l Did EINER EE 2l 52 DISASSEMBLY AND ASSEMBLY PROCEDURES
5. Trimethylamine Tungsten hexafluoride Uranium hexafluoride Vinyl bromide Vinyl chloride Vinyl fluoride Water vapour Xenon Hexafluoroethane Trimethyl borate Trimethyl phosphite Titanium tetrachloride NOTE AFC 260 261 User s Manual Formula C4H4 Kr CH4 CH30H CH3NH 5 CH3Br CH3CI CH3F CH3SH SICH3CIg Ne NO N2 NO N204 NF3 N20 02 B5Hg C5H12 C2F4 PH3 C3Hg SiH4 SiCI4 SiF4 50 SFg SCH CH3 3N WFg UFg CoH3Br GH CoH3F H20 Xe Lafe B OCH3 3 P OCH3 3 18 Densit 2 51 3 73 0 7166 1 430 1 392 4 29 2 28 1 53 2 146 6 670 0 900 1 3402 1 2503 3 675 3 675 3 173 1 98 1 429 2 9 3 4 4 3 4 45 1 523 1 98 1 89 1 438 7 58 4 68 2 91 6 5 6 047 2 7 13 2 15 76 4 83 2 82 2 060 0 804 5 88 6 16 4 64 5 54 8 465 Table 3 1 Conversion factors continued on next page When using gases marked with an asterisk use low pressure AFC 50 00 C cal g degC Sp Heat g I 0 339 0 321 0 0596 1 45 0 528 0 722 0 3277 0 583 0 400 0 491 0 113 0 56 0 200 0 60 0 267 0 67 0 2506 0 508 0 164 0 250 0 2460 1 460 0 236 0 98 0 2484 1 000 0 194 0 41 0 200 0 37 0 178 0 434 0 206 0 72 0 2183 0 996 0 565 0 17 0 38 0 21 0 192 0 33 0 140 0 44 0 2607 0 688 0 392 0 35 0 357 0 405 0 3188 0 596 0 125 0 228 0 168 0 35 0 149 0 67 0 1590 0 27 0 130 0 348 0 367 0 27 0 0951 0 22 0 079 0 22 0 123 0 46 0 202 0 48 0 241 0 551 0 445 0 817
6. U Sensor Extra outp Readout 0 5 VDC H5VDOC c 1N4007 1N4148 Power Common sa Signal Common ZA 100 Ground Setpant 0 5 VDC lt 4 Valve testp D 45VDC co 4 1 4007 Zener Testp BD136 R24 Seled in Seled in test test ar def 320k Actuator R12 must be 4120 but may be 390 Q or adjusted values in older versions Proprietary of ASM F reproduction forbidden ELECTRONIC SCHEMATIC AFC 260 Jan 1996
7. Fluoroform CHF3 3 125 0 173 0 506 34 Freon 11 CCI3F 6 3 0 1415 0 34 35 Freon 12 CCloF9 5 5 0 149 0 34 36 Freon 13 CCIF3 4 8 0 156 0 37 37 Freon 13Br CBrF3 6 8 0 1124 0 36 38 Freon 14 CF4 3 96 0 167 0 41 39 Freon 22 CHCIF5 4 05 0 156 0 43 40 Freon 114 CoCloF 4 7 7 0 163 0 22 41 Genetron 21 CHCIDF 4 64 0 144 0 41 42 Genetron 115 CJCIF5 7 1 0 1636 0 24 43 Germane 3 423 0 138 0 58 44 Helium He 0 1788 1 242 1 454 45 3 Helium 3He 0 135 1 65 1 45 46 Hydrogen Ha 0 0899 3 400 1 016 47 Hydrogen bromide HBr 3 60 0 085 1 01 48 Hydrogen chloride HCI 1 635 0 1937 0 981 49 Hydrogen fluoride HF 0 90 0 348 0 99 50 Hydrogen iodide HI 5 71 0 057 0 95 51 Hydrogen selenide H5Se 3 613 0 103 0 78 52 Hydrogen sulphide H2S 1 534 0 244 0 78 53 Isobutane 10 2 63 0 395 0 26 260 261 User s Manual 17 D 10 017 01 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 94 95 96 Name Isobutylene Krypton Methane Methanol Methylamine Methyl bromide Methyl chloride Methyl fluoride Methyl mercaptan Methyl trichlorosilane Neon Nitric oxide Nitrogen Nitrogen dioxide Dinitrogen tetroxide Nitrogen trifluoride Nitrous oxide Oxygen Pentaborane n Pentane Perfluoroethylene Phosgene Phosphine Propane Propylene Silane Silicon tetrachloride Silicon tetrafluoride Sulphur dioxide Sulphur hexafluoride Trichlorosilane
8. checks should be completed 1 Check all tubing is leak proof 2 Check the process sequence and proper function of all other gas components involved 3 Check the voltage of command signals and power supply to the mass flow controller 4 Check the appropriate gas type is being supplied at the rated pressure 5 Allow the mass flow controller to warm up for 20 minutes then check the zero level output 6 Use dry inert gas for test runs 7 Prior to using the mass flow controller for extremely corrosive gases purge with dry inert gas for one hour AFC 260 261 User s Manual 14 D 10 017 01 SECTION 3 OPERATION 3 1 SENSOR AND BYPASS The massflow sensor is a laminar flow device which forms together with the bypass the flowpath The splitting up of the flow is additive and independent of gas pressure and temperature The flow rate through the sensor capillary tube is measured by resistance thermometers wound on the outside of the tube These thermal sensitive resistors are part of a bridge circuit With no flow through the tube the bridge is balanced and the differential amplifier that follows the bridge gives zero volt output With flow the internal heat exchange is altered and consequently the temperature profile along the tube which causes a bridge output signal A linearity circuit corrects the possible inherent non linearity of the sensor The output signal is amplified to give 5 00 VDC at the required flowrate By me
9. common is jumpered to C Remove this jumper and use seperate common is advise everytime it is possible 5 Any DC voltmeter or recorder can be used to visualize the output signal Input impedance should be at least 5000 ohms 6 The control Input signal should be from any voltage source with maximum impedance 2500 ohms Table 1 Description of D connector pin functions AFC 260 261 User s Manual 11 D 10 017 01 2 3 2 SOFTSTART COMMAND If you have a non zero setpoint and the flow is stopped by a shutoff valve the mass flow controller will open fully to try and achieve the setpoint When the flow is restored the mass flow controller will be fully open and there will be a substantial overshoot see figure 2 6 flow setpoint without softstart with softstart time gt Figure 2 6 Effect of the soft start mode This can be avoided by using the softstart feature Externally connecting pins 10 and 12 will cause the mass flow controller to shut completely regardless of the actual setpoint The controller will close almost instantaneously The connection can be made by the same switch that operates the shutoff valve A typical arrangement is shown in figure 2 7 When the shutoff valve is reopened pins 10 and 12 will be disconnected and the controller will open to control at the setpoint NO shutoff valve gt gt power supply shutoff valve Figure 2 7 Softstart circuit AFC 260 261 User s Manual 12 D 10 017
10. gas for which the mass flow is calibrated to work with Why using a bypass Because the sensor element can only measure small flow typically 5 sccm So the bypass allow to measure greater amount of flow On a 5 sccm full scale mass flow there is no bypass all the gas flows thru the sensor On a 100 sccm full scale mass flow the bypass is adjusted as when 100 sccm flow thru the mass flow 5 sccm will flow thru the sensor and 95 sccm will flow thru the bypass 7 3 SENSORS PRINCIPLES Basically the sensor uses the thermal properties of a gas to directly measure the mass flow rate The sensor uses the basic principle that each gas molecule has a specific ability to pick up heat This property called the specific heat Cp directly relates to the mass and physical structure of the molecule and can be determined experimentally The specific heat is well known for many gases and is generally insensitive to changes in temperature or pressure By adding heat to a gas and monitoring the change in temperature the mass flow rate can be determined To illustrate this concept take the case of cool gas flowing through a heated tube Mathematically the heat loss can be described by the First Law of Thermodynamics Cp AT Where q is the heat lost to the gas flow F is the mass flow Cp is the specific heat for a constant pressure AT is the net change in gas temperature as it traverses the tube It is important to realize that both
11. not close adequately check the valve heater voltage this may be increased to a maximum of approximately 10 VDC AFC 260 or 15 VDC AFC 261 by reducing the current limiting Resistor R25 If valve still will not close the seat may be contaminated For further repair see 5 4 4 4 CHANGE OF CALIBRATION 1 If it is desired to calibrate the unit for a gas other than the original calibration there may not be sufficient adjustment in the GAIN potentiometer to obtain 5 0 VDC at full flow In such case center the GAIN potentiometer and replace R10 the unit following the instructions 4 2 2 If it is necessary to change the range of a flowmeter or controller beyond the electronics adjustment capabilities one has to replace the bypass assembly to produce the nominal sensor output at full scale flow In addition the valve may have to be replaced The bypass is a preadjusted assembly which can be removed and reinstalled with the use of a screwdriver Also bypass washers may be added or removed in such a way that the number of grooves that is added or removed is proportional to the shift in flow range There are three types of washers with one with ten and with forty grooves after such replacements recalibration as per instructions 4 2 is absolutely necessary 4 5 DYNAMIC RESPONSE ADJUSTMENT After replacement of a valve recalibration of a unit to a different range of gas it may be necessary to readjust the feedback control circuit in ord
12. open Now the flowcontroller works essentially the same as a flowmeter Adjust the flow to exactly the full scale value Adjust the GAIN potentiometer R9 to give 5 00 VDC output Recheck ZERO step 3 At half of the full scale flow the meter should give 2 50 VDC output If not adjust the LINEARITY potentiometer R29 After this ZERO and GAIN should be checked and readjusted of necessary ZERO and GAIN should normally be independent of LINEARITY Continue these steps until all points are within desired calibration Flowcontrollers can also be calibrated while working as flowcontrollers First calibrate ZERO as per step 3 Then with 5 00 VDC setpoint adjust GAIN until the actual flow is equal to the required flow rate Next with 2 50 VDC setting adjust LINEARITY Note that output stays at the setpoint value now while flow varies 4 3 VALVE ADJUSTMENT 1 Plumb the inlet side of the controller to a regulated supply of the correct gas Connect the reference flowmeter in series or monitor the flow as measured by the controller Bring the Inlet pressure to 0 3 0 4 bar AFC 260 or 0 6 0 8 bar AFC 261 and disconnect the valve lead wire While gently turning the adjustment nut on top of the valve bring the flow to 10096 of the required value Reconnect the lead wires AFC 260 261 User s Manual 19 D 10 017 01 3 Check that the valve will shut off to less than 296 of F S flow at all 0 3 and 3 bar 4 If the valve does
13. output and almost zero at zero and full scale output Output voltage and setpoint voltage are compared by Op Amp A If flow is too low T2 closes further to decrease the current through the control valve and vice versa R25 forms a current limiter as all valves close at different voltages R25 is to be selected in shut off tests C6 and R24 reduce the gain of C during a flow and or setpoint transient providing a slowly changing valve control voltage which in turn gives a gradual change in flow rate D2 and D3 protect the electronics from damage in case and 15 V power is reversed Op Amps A B and C are parts of a quad i c 14 pins DIL The commercial available i c enhances field service and reduces down time as replacement hardly effects accuracy 3 4 CONVERSION DATA If a mass flow meter or controller calibrated e g for N2 200 sccm has to be used for working with another gas say X conversion data can be used to calculate the actual flow of gas X AFC 260 261 User s Manual 15 D 10 017 01 The achieved accuracy is less than 1 standard calibration but always better than 4 The formula for calculating the flow of gas X is in this example Actual flow of gas X Actual f low of C N Where the flow are sccm or slm and C X and are the tabulated values of the conversion factors In this example when X is say C 0 746 Actual flow of CO 0 746 Actual flow of N 1 000 So the act
14. 15VDC 5 25mA 15VDC 25mA 15VDC 5 180mA 15VDC 5 180 Setpoint L Setpoint Sigal 0 1 5 VDC engen El t 196 of Full Scale t 196 of Full Scale Gas T Range 5 40 C 5 40 C 5 40 C T coefficient less than 0 1 C less than 0 1 C less than 0 1 C Gas Pressure 10 bars max 10 bars barr max 10 bars max 0 5 3 at diff 1 0 3 at diff 0 7 3 at diff for H2 1 2 3 at diff for Ho 0 1 atm typ 0 1 atm typ Du EE sakke Rate 2 10 scc sec 2 10 scc sec 2 10 scc sec Table 1 2 Specifications values For a differential pressure under 1 5 bar 22 psi it is recommended to use a QUALIFLOW mass flow controller AFC 50 00 to control 20 slm full scale flow AFC 260 261 User s Manual 5 D 10 017 01 Standard Gas table AFM 360 AFC 260 AFM 361 AFC 261 SCCM SLM 02 10 0 2 10 0 04 20 0 4 20 0 0 6 30 1 50 2 100 p p 4 200 p KE EE 20 1000 p 40 2000 p 60 3000 100 5000 HM _ Table 1 3 Standard ranges values VCR 1 4 MM VCR 1 4 FM 1 4 Table 1 4 Part numbers of AFC 260 261 and AFM 360 361 Note AFC and AFM are delivered with Viton seals except NH3 mass flow which are delivered with neoprene seals Please contact your local representative for other kind of seal material LT 260 360 MM 260 360Mod 260 360 SWG 261 361 261 361 Mod 261 361 SWG 1416 mm 2126 1467 Weight 500 gr 500 gr 500 gr 950 gr 950 gr 950
15. ATIBLE COUPLINGS The AFC 260 261 mass flow controller or AFM 360 361 mass flow meter normally come with 1 4 male VCR compatible couplings on both sides To install the AFC AFM follow the steps listed below Refer to figure 2 2 1 Check the gland to gland space including the gaskets AFC 260 261 User s Manual 8 D 10 017 01 2 Remove the plastic gland protector caps 3 a When using loose VCR original style gaskets insert the gasket into the female nut b For VCR retainer gaskets snap the gasket onto the male coupling See figure 2 2 Tighten the nuts finger tight Scribe both nut and body in order to mark the position of the nut While holding the body with a wrench tighten the nut a 1 8 turn past finger tight for 316 stainless steel and nickel gaskets b 1 4 turn past finger tight for copper TFE and aluminium gaskets o gos VCR retainer gasket Figure 2 2 VCR compatible couplings AFC 260 261 User s Manual 9 D 10 017 01 2 2 1 2 SWAGELOK COMPATIBLE COUPLINGS On request the AFC 260 261 mass flow controller or AFM 360 361 mass flow meter can be supplied with 1 4 male Swagelok compatible couplings In this case polished stainless steel tubing must be used to ensure a leak tight system The mounting instructions are as follows Insert the tubing to the shoulder inside the fitting Check that the ferrules are positioned as shown in figure 2 3 Tighten the nuts finger tight Scribe both nut and bod
16. Table 6 1 symptoms causes and solutions AFC 260 261 User s Manual 24 D 10 017 01 Model Valve closing R25 1 W 596 voltage Up to 6 VDC 6 to 7 VDC 7 to 8 VDC 15VDC Table 6 2 Values of the valve resistance 25 Note Do not exceed 10 VDC on AFC 260 valve R25 must be 30 or greater to prevent severe damage distortion or burn out Overpowering the valve unnecessarily may reduce its life and reliability CAUTION When the gas supply has been shut off or when purging a hydrogen controller with another gag such as Nitrogen do not command less than 10 of Full scale as severe damage to the control valve may result AFC 260 261 User s Manual 25 D 10 017 01 SECTION 7 GENERAL PRINCIPLES 7 1 MFC amp MFM PRINCIPLES Mass Flow Controllers MFCs are used wherever accurate measurement and control of a mass flow of gas is required independently of flow pressure change and temperature change in a given range Mass Flow Meters MFMs are used wherever accurate measurement of gas is required without control of the flow which is done by another device To help understand how an MFC works it can be separated into 4 main components a bypass a sensor an electronic board and a regulating valve feedback circuit FIG 1 Schematic of the mass flow controller The bypass the sensor and one part of the electronic board are the measurement side of the mass flow controller and makes a Mass F
17. VERAL SYMPTOMS Possible Cause No output Faulty meter Read output at pins 3 and 2 directly with alternate meter No actual Flow Check pressure valve positions line or filter blockage Sensor clogged Follow 5 3 Valve closed Follow 5 4 Electronics failure See below Faulty power supply Check input output voltages 15VDG 5VDC Maximum signal Check valve voltage as measured between 150 and across valve lead wires Valve should 200 of full scale close when voltage rises to 6 10 VDC AFC 260 11 15 VDC AFC 261 a Indication correct flow Valve defective Lower voltage indicates lack of is high closing command or electronic failure repair electronics 14 15 VDC indicates open circuit on valve heater AFC 260 Measure DC resistance Open resistance on sensor on AFC 261 Replace Valve b Indication erroneous element Replace sensor Electronics failure Electronics not adjusted See below Signal offset at zero flow Contamination Follow 4 2 Valve will not close Open valve heater Follow 5 1 or 5 4 Check d c resistance 100 ohms AFC 260 Electronic failure 125 ohms AFC 261 Mechanical damage from See below overpressure or other Adjust valve 4 3 or replace valve cause 4 4 Operation on wrong gas often the case when Test on proper gas tested with H5 He or Ar AFC 260 261 User s Manual 23 D 10 017 01 Valve will not open Contamination Electrically commanded Follow 5 1 or 5 4 closed or potent
18. ans of bypass substitution the flow through the sensor is made almost the same for all the flow ranges 3 2 CONTROL VALVE AFC 260 and AFC 261 flow controllers are equipped with a completely interchangeable control valve The valve housing contains the shut off plunger and the actuator whereas the orifice is situated in the base block In case of contamination or clogging the valve can be taken out giving access to the seat and the shut off plunger The critical places can be cleaned even polished and the valve can be reinstalled See cleaning instructions 5 4 3 3 ELECTRONICS In the schematic see last page the sensor elements are shown between u c and d R1 and R2 complete the bridge together with potentiometer R3 ZERO for balancing of the bridge OpAmp C amplifies the differential voltage Potentiometer R9 GAIN together with R8 R10 and R5 determine the D C gain R11 with C4 give the differentiating action a sudden change in the bridge voltage causes an extra gain AC gain The time constant of this transient is determined by R11 At the factory this resistor is selected during transient tests for every individual meter or controller Z1 and R14 R12 R13 determine the current through the sensor As not every sensor bypass pair is completely linear linearizing circuit Op Amp B R15 until R20 varies the sensor current as a function of the output voltage The influence of R19 LINEARITY is maximal at half of full scale
19. carefully Qualiflow guarantees that all glands have been individually inspected and are scratch free e Fitting procedure the fitting procedure set out in the manual must be followed meticulously Specifically the purge procedure is very important if corrosive gases or toxic gases are used AFC 260 261 User s Manual 32 D 10 017 01 f The mass flow must not be dismounted the MFC warranty will be invalidated if the seal between the MFC block and cover is torn 8 2 SERVICES QUALIFLOW Products Engineers will help you to solve your problems regarding operation calibration connection gas flows gas mixture etc We deliver technical support or maintenance within 24 hours Visit www qualiflow com and find your nearest repair and calibration center AFC 260 261 User s Manual 33 D 10 017 01 SECTION 9 PARTS LISTS AND DESCRIPTION AFC 260 261 User s Manual 34 D 10 017 01 BO N LY Ly LY Q H H H 4 NOTBEUSED FOR ENGINEERING DESGN OR MANUFACTURE IN WHOLE OR IN PART THSDOCUMENTCONTAINS INFORMATION PROPRIETARY TO QUALIFLOW SA AND SHALL WITHO UTWRITTEN CONSENTOF QUALIFLOW SA REV DESCRIPTION DATE DES Tolerance Ra Finish Finition QUALIFLOW ADVANCED FLOW CONTROL Des FL Date 25 8 98 DESIGNATION Chk V rt Date AFC 260 Date Approuv SCALE F REV Echelle 2600VFM010L007H Material Matiere A 3 FO LIO 1A All dimensionsare in mm D Sensor C Sensor
20. ce change are convert in voltage by a simple wheatston bridge working zone Sensor measurment 5 sccm Gaz Flow Sensor response AFC 260 261 User s Manual 28 D 10 017 01 For flow under 5 sccm the measurement is proportional to the flow with a coefficient which depends on p Volumic mass of the gas specific heat for a constant pressure N spin factor Constant which depend of the molecular structure of the gas and compensates for the temperature dependence of Cp Value of N Monoatomic gas 1 04 Diatomic gas 1 00 Triatomic gas 94 Polyatomic gas 88 For flow higher then 5 sccm the sensor is first non linear then the measurement starts to decrease with flow because the gas flow is too fast and cool the 2 winded resistances instead of cooling the first one and heating the second one This is the reason why bypass is necessary for higher full scale than 5 sccm Also the fact that the coefficients N and Cp are different from one gas to another explains why mass flow can NOT be changed from one gas to another without using a special coefficient to converter the measurement or recalibrate the mass flow Because of sensor saturation if flow is ten time the full scale output will be almost no flow This will never happen on a mass flow controller as the valve of the mass flow will act as a restriction and will not allow the gas to flow ten times the full scale But it can easily happened on a mass flow meter as i
21. cleaning and recalibration After 3 or 4 years when the unit is run with a ultra clean and non corrosive gas After 1 or 2 years when the unit is run with a low purity gas and or a corrosive gas Cleaning can be performed by removing the unit from the system cleaning in and outlet fittings separately and pumping alternately reverse and forward for 5 minutes in each direction with a solvent system one micron maximum absolute filtration Next the unit must be blown with 2 for 30 minutes minimum Reinstall cleaned fittings In extreme cases of contamination it may be necessary to separately clean the sensor the bypass and the valve 5 2 DISASSEMBLY AND ASSEMBLY PROCEDURES Refer to exploded views 1 Unscrew in and outlet fittings 2 Remove the sensor screws after having the lead wires unsoldered from the p c board Handle the sensor with care 3 Remove the screws which hold the valve print plate to the base block after unsoldering the valve leads wires Carefully remove the valve body from the base block Remove the two o rings Unscrew the bypass Do not damage the thread or the bypass washers The valve can be further take apart by unscrewing the adjustment not completely in pulling the tube holder with actuator tube and heater element carefully out of the valve housing Note If o rings are dirty cut or cracked they have to be exchanged with appropriate new ones The sequence of assembling is following above instr
22. e shut off ball and the seat in the base block can be examined The shut off ball can be cleaned with alcohol freon or even a HF solution 596 HF 9596 deionised water Do not completely immerse the assembled valve housing in a solvent as the heater element can be destroyed To get access to the inside proceed as indicated in 5 2 6 The conical seat in the ball can be treated with solvent and a felt tip If appropriate polishing equipment is available the seat and shut off ball can be polished After polishing the parts must be cleaned If the critical parts are unfortunately corroded or attacked too much replace Afterwards follow assembling instruction 5 2 and adjustment instruction 4 3 AFC 260 261 User s Manual 22 D 10 017 01 SECTION 6 TROUBLESHOOTING 6 1 INITIAL CHECK 1 Check set up and procedure against connection instructions 2 1 and 2 2 Permanent damage to the unit may result if purging procedures are not followed or if line power is accidentally applied to the signal leads 2 Test line cord for compliance with pinassignment and continuity from all wires to correct pins Use hipot tester to check for any pin to pin shorts during this test flex the cable coming out of the connector to find intermittent shorts 3 Check insulation resistance from pins to base All except pin 1 should exceed 50 MQ at 50 VDC Pin 1 to base should measure less than 1 4 Proceed as indicated in 4 2 points 1 2 and 4 6 2 SE
23. er to optimise the dynamic response and stability performance of a controller This entails reselecting R11 and R24 during transient tests This is best accomplished by setting the inlet pressure to 20psi or the known operating pressure while switching the setpoint from 5096 to 10096 of full scale and vice versa and noting the response The flowmeter section valve and maximum valve voltage must have been previously set jm After calibrating the flowmeter section and selecting R25 install C6 220F 25 VDC and R24 20k and R11 1k with resistance substitution boxes 2 Alternately give 10096 and 5096 setpoint and observe the output and response Best performance is when about 596 overshoot is observed Reducing R11 reduces the time constant and overshoot but increases output ripple 3 Once R11 has been selected and installed increase R24 to the highest possible value Increasing R24 increases the dynamic gain of the controller thereby improving the dynamic response to changes in upstream pressure and or setpoint Too high a value will result in output oscillation and instability Typical values are for Hydrogen and Helium R11 about 400 to 700 R24 30 to 100 For nitrogen and other gases R11 about 400 to 700 O R24 60 to 360 AFC 260 261 User s Manual 20 D 10 017 01 SECTION 5 MAINTENANCE 5 1 GENERAL No routine maintenance is required to be performed on the meters or controllers other than occasional
24. f there is no restriction on the gas line nothing in the mass flow meter will limit the gas flow 7 4 BYPASS PRINCIPLES Acting as a restrictive element the bypass is composed of a series of capillary tubes washers held in a special bypass ring The ring fits around the body and may hold up to 24 tubes The number of tubes and their diameter depend on the customer s specifications of gas type and flow range For high flow rates the bypass tubes are replaced by a screen bypass Bypass ring Bypass tubes Bypass tubes AFC 260 261 User s Manual 29 D 10 017 01 O O 0 a Bypass washers equivalent to several thin tubes The bypass principles are based on the laminar flow theory When flow is laminar the flow is proportional to the differential pressure between inlet and outlet of the tube Fn P 3 1 Piown p Volumic mass of the gas Viscosity of the gas length of the tube R radius of the tube So when a sensor tube radius Rs length Is and a bypass tube are in parallel radius Rb length Ib the flow in the sensor tube is proportional to the flow in the bypass However this is true only if the flow is bi so if the tube are small enough This is way bypass are made by several thin tube instead of only one tube It is important to notice that a mass flow meter or controller measure the flow thru the sensor which is not the total flow but only one part of the flow sp
25. gr Table 1 5 dimensions of AFC 260 261 and AFM 360 361 AFC 260 261 User s Manual 6 D 10 017 01 SECTION 2 INSTALLATION 2 1 INTRODUCTION This section is made of four parts and contains all the information necessary to install the AFC 260 261 mass flow controller or AFM 360 361 mass flow meter e 2 1 unpacking e 2 2 mechanical installation e 2 3 electrical installation 2 4 checks before start up 2 2 UNPACKING The AFC 260 261 mass flow controller or AFM 360 361 mass flow meter are manufactured under cleanroom conditions and has been packed accordingly Upon receipt the cardboard packing should be checked for damage If there is visible damage please notify your local QUALIFLOW sales office In order to minimize contamination of cleanrooms the unit has been packed in two separately sealed plastic bags The outside bag should be removed in the entrance to the clean room The second bag should be removed when you install the unit 2 3 MECHANICAL INSTALLATION 2 2 0 GENERAL Most applications will require a positive shutoff valve in line with the mass flow controller Pressurized gas trapped between the two devices can cause surge effects and consideration must be given to the sitting of the shutoff valve upstream or downstream in relation to the process sequencing As far as the process parameters permit it is recommended that you install an in line filter upstream from the controller in order to preve
26. iometer Check command signal pins A and shorted B and pot Check for electronics Clogged inlet fitting screen failure appearing as closed valve Valve controls at higher Contamination Clean filter screen flow rates but not at Erosion or corrosion minimum improper adjustment or Follow 5 1 or 5 4 inadequate drive Follow 5 4 Adjust 4 3 Reduce R25 Valve oscillate or hunts pressure regulator Replace Improper system dynamics Reduce upstream pressure regulator due to excessive inlet setting pressure Improper dynamics in See 4 5 electronics General failure or Power supply voltage not Check 15 VDC 15 VDC and 5 00 miscalibration nominal VDC Flow indication saturated Bridge or sensor failure Check sensor resistance 0 7 or 12 VDC Voltage Yellow to common 8 to 10 regardless of flow VDC Pin 6 to common should read Component Failure 6 2 2 VDC Valve drive open or TS2 open or short IC LM Check R3 R9 other components saturated 0 or 6 10 VDC 324 failed and solder joints AFC 260 0 or 11 15 Check TS2 LM 324 and other VDC AFC 261 components All circuit functional but Contamination or as a Adjust see 4 out of calibration result of cleaning or repairing Unit controls but output 5 00 VDC not nominal Check supply Adjust if necessary voltage does not agree with potentiometer setting Large input voltage offset Check and replace if necessary in Op Amp A C6 leaks Replace
27. lit by the bypass according to last equation In this equation radius of the sensor tube and bypass tube is at power 4 Consequently any deposition in one of the tube changing the diameter will change the accuracy of the measurement Also because of the need to have a laminar flow bypass tube and sensor tube may have clogging This why mass flow meter and controller must be used with clean filtered gases 7 5 CONTROL PRINCIPLES The electronic compares the amplified mass flow rate value measured by the sensor to the desired set point This comparison generates an error signal that feeds the regulating valve The difference is used to drive the control valve The control valve will proportionally open or close until the output is equal to the setpoint Note that valve can be normally open or normally close This is the position that will have the valve when the mass flow is not connected on power supply The valve can be actuated by a magnetic solenoid Then it can be normally open or normally close and response time of the valve itself is almost instantaneous In practise response time of the mass flow controller is limited by the response time of the sensor As sensor is based on thermal exchange it takes 1 to 5 s for the sensor to measure a gas change Several techniques allows to increase this response time and allow to get on the best mass flow response time bellow 5s The valve can be also made by a heating wire which heat a small tube
28. low Meter The regulating valve and the other part of the electronic board are the controlling side of the mass flow controller and exist only on a Mass Flow Controller So every Mass Flow Controller includes a Mass Flow Meter 7 2 MEASUREMENT PRINCIPLES The flow is divided between a heated sensing tube the sensor where the mass flow is actually measured and a flow restriction or bypass where the majority of flow passes The bypass is designed in a way that flow thru the sensor and thru the bypass is always proportional to the flow range for which the mass flow is build The sensor is designed to deliver an output voltage almost proportional to the gas flow circulating thru it which is due to the bypass design proportional to the total flow circulating thru the mass flow meter or controller The electronics board amplifies and linearizes the sensor signal so the output of the electronics board named readout gives a signal proportional to the total flow circulating thru the mass flow meter or controller Most of the time this signal is a 0 5 V voltage signal 0 means no flow and 5 V means Full scale of the mass flow The full scale is the maximum flow for which the mass flow is designed and calibrated to work with a good accuracy It is AFC 260 261 User s Manual 26 D 10 017 01 always written on the stickers which are on the top of the cover and the side of the mass flow stainless steel base Also written on the sticker is the
29. nt contamination The AFC 260 261 mass flow controller or AFM 360 361 mass flow meter can be mounted in any position The atmosphere should be clean and dry The mounting should be free from shock or vibration Mounting dimensions are shown in figure 2 1 Prior to installation ensure that all the piping is thoroughly cleaned and dried Do not remove the protective endcaps until you are ready to install the controller 109 AFC 260 261 User s Manual 7 D 10 017 01 Figure 2 1 Dimensions of the AFC 260 or AFM 360 mass flow meter Type Outlet IA B C Modu C Female Male VCR 141 6 32 95 32 45 VCR Standard Male VCR Male VCR Swagelok Swagelok Swagelok 25 SEMI CONDUCTOR MATERIALS MONTPELLIER FRANCE Figure 2 2 Dimensions of the AFC 261 or AFM 361 mass flow meter Type C Female VCR Male VCR 212 6 Standard Male VOR Male VCR Swagelok Swagelok Swagelok 2 2 1 INSTALLATION WARNING Toxic corrosive or explosive gases must be handledwith extreme care After installing the mass flow controller the system should be thoroughly checked to ensure it is leak free Purge the mass flow controller with a dry inert gas for one hour before using corrosive gases Important When installing the mass flow controller ensure that the arrow on the back of the unit points in the same direction as the gas flow 2 2 1 1 VCR COMP
30. pted for repair or warranty without a decontamination and purge certificate Each MFC is individually checked visual inspection of fittings helium leak test and flow calibration Qualiflow shall not be responsible for any damage caused by gas leakage or the use of a dangerous gas Users are responsible for following the safety rules applicable to each gas they use Improper use of a Qualiflow MFC will void the warranty and MFCs that have been damaged as a result of improper use will not be replaced by Qualiflow Specific warranty requirements are as follows a Gas must be clean and particle free which means a filter must be fitted in the gas line upstream of the MFC b Gas must comply with the following pressure specifications i Gas pressure must never exceed 10 bars ii Differential pressure must be more than 500 mbar for full scale flow through the MFC valve iii Differential pressure must be less than 3 bars for the MFC valve to regulate without gas flow oscillation iv Pressure at the mass flow inlet must be regulated by an accurate pressure regulator to prevent gas flow oscillation c Electrical connection requirements are as follows i The system must be wired carefully non observance of the pinout may irreversibly damage the electronic board inside the MFC in which case the warranty will be invalidated ii A stable power supply is required with ripple below 5mV d Gas connections the VCR gland must be handled
31. qualiflow AFC 260 AFC 261 AFC 260 261 User s Manual QUALI FLOW Montpellier headquaters 350 rue A Nobel BP7 34935 MONTPELLIER CEDEX 9 France tel 33 4 67 99 47 47 fax 33 4 67 99 47 48 QUALI FLOW I nc 24 Goose Lane TOLLAND CT 06084 CALIFORNIA USA tel 1 860 871 92 33 fax 1 860 871 92 33 QUALI FLOW Technology Center 909 Boggs Terrace Fremont CA 94539 CALIFORNIA USA tel 1 510 440 93 74 fax 1 510 440 93 75 QUALI FLOW NRT Korea 10 Block 17 Lot Namdong Ind CLX 623 16 Namchon Dong Namdong Ku KOREA tel 82 0 2 3401 6491 fax 82 0 2 3401 6493 AFC 260 261 User s Manual D 10 017 01 Identification User s Manual AFC 260 AFC 261 AFC260 amp 261 Manual doc Control Approved Olivier L onel 07 02 01 Pierre Navratil 07 02 01 Pascal Rudent 07 02 01 History Olivier L onel 24 08 00 Initial Version 00 Issued Olivier L onel 07 02 00 Exploded View added 01 Issued 2000 QUALIFLOW Montpellier France This document contains information proprietary to QUALIFLOW and shall not be used for engineering design procurement or manufacture in whole or in part without consent of QUALIFLOW AFC 260 261 User s Manual 3 D 10 017 01 SECTION T INTRODUCTION unndra 5 LI SURVEY OF TYPES AND GAS RANGES eti tita ee geh 5 1 2 SPECIFICATIONS teet pesto pue 5 SECTION 2 INSTALLATION
32. the specific heat and the flow rate determine the amplitude of the heat flux As the mass and physical structure of molecules vary widely from gas to gas so does the specific heat Cp For the same molar flow rate the heat flux can differ significantly for different gases If this heat flux is monitored the amplitude can be converted into an electrical signal Given that the specific heat is known for the gas then the mass flow rate can be determined directly from the electrical signal Now the MFC sensor includes capillary tube wound with two heated resistance and thermometers measuring the change in temperature distribution created by the gas flowing inside this tube heating current Sensor schematic AFC 260 261 User s Manual 27 D 10 017 01 For zero flow the upstream and downstream temperature will be equal The windings are heated electrically to 80 above the ambient temperature When the gas is flowing the upstream region cools down whereas the downstream region heats up causing a temperature gradient along the length of the tube see the sensor temperature profile figure 2 Winded Hy Sensor tube Flow ir gt LLL TEMPERATURE NO FLOW SR 1Qsccm 2 Winded Sensor temperature profile The coils of the heating resistances are made with a thermal sensitive wire so that the temperature differences due to the flow are directly converted into resistances change Those resistan
33. then dilation will move a ball at the end of the tube This kind of valve can be only normally open and is quite slow AFC 260 261 User s Manual 30 D 10 017 01 Mass flow controller using such valve will have response time around 5 to 6 s for flow bellow 5 sim and up to 10 s for flow up to 5 sim However this technology is simple and reliable and can be recommend for many low cost application when response time is not critical AFC 260 261 User s Manual 31 D 10 017 01 SECTION 8 WARRANTY AND SERVICES 8 1 PRODUCT WARRANTY 1 Qualiflow products are guaranteed against defects in materials and workmanship for a period of one year from the date of shipment if used in accordance with specifications and not subject to physical damage contamination alteration or retrofit Buyers undertake to check and inspect the goods and to notify Qualiflow of shipment incidents by fax phone or e mail as soon as possible after receipting the goods During the warranty period products must only be repaired by authorized Qualiflow service centers otherwise the Qualiflow product warranty will be invalidated Repairs will be performed free of charge during the one year warranty period If MFCs are out of warranty Qualiflow will notify the owner of replacement or repair costs before proceeding Factory service and repairs are guaranteed 90 days The warranty excludes consumable materials and wear parts in teflon viton etc No MFC will be acce
34. ual flow of C02 if measured with a unit that was originally calibrated for No is obtained by multiplying the output by 0 746 AFC 260 261 User s Manual 16 D 10 017 01 Name Formula Densit Sp Heat g l C cal g degC 1 Acetone C3HgO 2 59 0 310 0 340 2 Acetylene C2H2 1 169 0 40 0 58 3 Air 1 2929 0 2401 1 000 4 Allene C3H4 1 81 0 358 0 42 5 Ammonia NH3 0 7710 0 519 0 68 6 Argon Ar 1 7842 0 1246 1 453 7 Arsine AsH3 3 481 0 1178 0 666 8 Boron trichloride BCl3 5 26 0 130 0 40 9 Boron trifluoride BF3 3 1 0 158 0 56 10 Butane C4H10 2 65 0 404 0 26 11 I Butene C4Hg 2 54 0 368 0 29 12 Carbon dioxide CO 1 977 0 201 0 74 13 Carbon monoxide CO 1 2500 0 249 1 000 14 Carbon tetrachloride 6 86 0 129 0 309 15 Carbonyl fluoride COF 2 96 0 170 0 544 16 Carbonyl sulphide COS 2 70 0 169 0 64 17 Chlorine Clo 3 209 0 116 0 83 18 Chlorine trifluoride CIF3 4 14 0 164 0 403 19 Chloroform 5 33 0 32 0 388 20 2 2 2 34 0 264 0 44 21 C3Hg 1 878 0 316 0 460 22 Deuterium Do 0 1800 1 728 0 999 23 Diborane BoHg 1 24 0 495 0 44 24 Dichlorosilane 2 4 54 0 141 0 43 25 Dichlorodimethylsilane Si CH3 9Clo 5 754 0 2029 0 234 26 Dimethylamine CH3 9NH3 2 03 0 362 0 370 27 Dimethylether CH3 90 2 08 0 3367 0 390 28 Ethane CoHg 1 352 0 415 0 49 29 Ethyl chloride CoH5Cl 2 90 0 234 0 40 30 Ethylene C2H4 1 258 0 366 0 59 31 Ethylene oxide C2H40 1 95 0 259 0 54 32 Fluorine F2 1 094 0 1974 0 929 33
35. uctions in the reverse direction oot Caution The sensor capillary sometimes extends beyond the seals o rings When positioned on the base without verifying that capillary ends fit in the holes in the base the capillary can be bend or damaged Therefore center the sensor by means of the mounting screws hold it up and then fasten the screws Reassembling of the valve assembly into the base block should always be done with the adjustment not fully opened Fully turned anticlockwise Afterwards follow up valve adjustment procedure 4 3 5 3 SENSOR CLEANING AND REPLACEMENT If it is determined that the sensor is contaminated flush with a solvent in hypodermicneedle while running a small wire 0 15 mm diameter available on request Do not immerse the entire sensor assembly in a solvent the solvent will keep under the cover and destroy or at least change the sensor characteristics Slow dry with nitrogen If the sensor resistance has changed or even open circuit is measured the assembly should be replaced The measured resistance between red and green R1 and between red and yellow R2 must be between 160 and 190 O and AR R2 R1 must be less than 1 Q Check also that there is no short circuit between the tube and the red wire AFC 260 261 User s Manual 21 D 10 017 01 Examine the sensor seals and replace when damaged 5 4 CONTROL VALVE CLEANING AND REPLACEMENT After having taken the valve out of the base the status of th
36. y in order to mark the position of the nut Tighten the nuts 1 and 1 4 turn while holding the body with a wrench FR E e Figure 2 3 Orientation of Swagelok compatible couplings Ok keng 2 4 ELECTRICAL INSTALLATION 2 3 0 GENERAL It is important to read section 2 3 ELECTRICAL INSTALLATION before connecting the AFC 260 261 mass flow controller or AFM 360 361 mass flow meter so that you understand the electrical configurations that are possible Within this section there are the following sub sections connections softstart command pressure control ratio control read out using a digital voltmeter 2 3 1 CONNECTIONS The standard AFC 260 261 mass flow controller or AFM 360 361 mass flow meter has a cardedge connector The pin arrangement is shown in figure 2 4 AFC 260 261 User s Manual 10 D 10 017 01 Figure 2 4 Cart dedge connector pin arrangement Table1 gives a more detailed explanation about the functions available on every pins Cardedge connector 1 Case Ground A Control Input 0 1 5 VDC 2 Common B Common valve 3 Output O 5 VDC C Common 4 15 VDC D Valve test point Soft start connection 6 Zener Test Point F 15 VDC 7 J Sensor Up stream 8 K Sensor Common 9 L Sensor Downstream 10 Extra Output Notes 1 For vacuum pressure control applications See 2 3 3 kkkk 2 Soft start connection See 2 3 2 3 Not available in earlier PC boards 4 Valve
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