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1. 25 4 315 523 21 22 END PROCEDURES GETSET INPUTS SET POINT FROM THE THUMBWHEEL BEGIN REPEAT BEGIN DUMMY S SETING SETPT INTECERCTO0D amp INTZGER HS3 SETPT SETPT 1D INTEGCRCB2 SETPT zSCTPT INTEGEPR4H1 IF 5 0 THEN IF SETPTX100D THEN EXIT 81 0 2 0 DUMMY zLEDOUT END RETURNCSZTPFY END PROCEDURE DELTA DELTA COMPUTES THE DIFFERENCE IN THE CURRENT READING FROM THE READING WHICH STARTED THE SAMLPLE BEGIN TLS ADCAYVE TIMES TIMEO 12 ADCAVE 4 ADCNEW I1 I2 DIV 2 I3 ADCNEH AUDCOLD IF 15 lt 0 THEN I3 I5 RETURNCI3 5 END PROCEDURE GETFLO GETFLO COMPUTES THE FLOW FROM THE CHANGE IN DISPLACMENT DURING A SAMPLE DIVIDED BY THE LENGTH OF THE SAMPLE BEGIN gt OSPNEWS DISP R2 zDSPNEW DSPOLD 8240 THEN R25 R2 3 IF 0 THEN TIMES 13 R1 OGSCALE R2 FLOW INTEGERIR1 IF FLOWCO THEN FLOW 0 IF FLOW 3999 THEN FLOW z9933 RETURN CFLOM1 5 END PROCEDURE DISP te DISP USES THE CALIBRATICN TABLE ACCESSED THROUGH TO FIND THE VOLUME DISPLACEMENT CORRESPONDING TO THE CURRENT REACING IT USES LINEAR INTERPCLATION
2. OF MICRCL COOL etes tata PROCEDURE MISTRI BINT4 15 15 THE MAIN CONTRCL AL508THM THE RESET PRDCDLOURZ JUMPS TO AFTER FC amp CR ON INITIALIZATION 4 PEGIN MISMSTART SAMPLE I ALS SFIPTI 93 ADCMINI MINMING lt 4 FLOPOSI VLYPOS3 DUMMYZzSTMON DUMMY TMOONi REPEAT BEGIN IF SAMPLE THEN BEGIN REPEAT BEGIN IF DELTA DELMIN THEN IF TIME DMINTIM TREN BEGIN FLOWI SETFLO ADCMINIINEWMING EXIT END IF TIME gt MAXTIM THEN BEGIN FLOW GETFLO ADCMINZ NEKMING EXITi 11 5 IF T1 lt gt GETSET THEN EXIT STPSIZ2 NOWVLVS DUMMY S FIKUPS DUMMY zSTMON DUMMYz FLOOUT SAMPLE zFALSE END ELSE BEGIN DUMMY I1 SETPT IF 1 lt gt 5 THEN BEGTN STPSIZI NEWVLVG DUMMYZ FIXUP DUMMYZ zSTMON END IF STPS1IZ 0 THEN BEGIN SUMMYZzSTMOFF 111 59101 DUMMY 2 11 lt 0 0 12 3 11 12 DIV 2 ADCOLDI ADCNEWi DSPOLD DISP DUMMY z STPOFF SAMPLE 5 185 185 187 188 189 130 191 192 193 194 195 196 197 198 199 200 201 202 203 20 205 206 207 208 299 210 211 212 213 215 249 250 254 255 255 257 253 259 260 345 352 462 468 434 494 518 524 525 541 47 551 lt 5
3. 0 2004 36091 81 252092004 3205 1 2 1020821147004 32051992 3 044 7212570330502 32 1622 0932 008 30232 1622 21982422 12221 86 02 413209 05221 352 9 92802 601 94 350021073A1FFFFE2A38023 29875F 1500211504197E2 3465FC 9000000004 3FD830354 06F 975 9521210407250A590C4A0E1110H211EA1 25014701501172F1843135314A5818541C5C1D761E47 04422100281F20202721RD2241232H240525E225FF 274329882ABF2B3C2DF120242F 70 309085 0555971 511232CL 32F 33343 B J 103ATFD 2180 1 51 5 1 4 7908321210L0FD3D1C U2E0057CD26080721730037C92371AA 77 80881 gt 108422111 0 90 4 1778434 6 4 24 06 781 77 3004 9BR63211593Ch11CE002000474FA7EDAAZ 9TRACF 57C0780200BIC2008C5 24BFDESDI180CT7TBEB 938421170789204688204 3FDF SCIF51F 300 10578 0060 ASF 7ACDD90AS7D5FDE1D1 30073FEDFA 0B8A35211A52D1D575377BRCD2 085F TACD2903C012 50035F EDA2CHU 1AS73005F IC1E DA27A0701CA nBC A21100000EDAAFDCSETEHCICATB2FATC3ES0A2100001FCDDD28300109C81CCB1D1F 300182 T212009CR1CCHIDIF 300102CHICCB1017 5001 03 1 CCB1D1F C93872002AF C95F AS17781F DA 7990821145 TTR 77 A100 DA 5E TBBTE21RQ03EDASFOECO TAFCBI517B830A24099300F 21C DSCBE 1 793222117t5C1722802FD454770FE202325CH7A2402EDS4 AE C9CHT A2DF AAF70C9B
4. 3 253 0123 EQU M TIM RI 264 0154 STIMER EQU M STIME 255 019 TMOON EAU M JI MN ON 266 0195 TMOOFF EQU M 267 0149 TMION EOU M JINLON 0185 TMiO0FF 269 DINA STMON EQU M JSTMON 270 01C4 STMOFF Eau M J3TMOFF 271 00 7 CICSET EGU M CTCSET 272 02 STOSET ERU M STOSET 273 02018 ADCSFT FRU M ADCSET 27 SIPSET M STPSET 275 0085 INTOFF EDU M JINTOFF 276 0073 INTON E OU M JINTON 0242 STPUP M JSTPUP 215 279 280 281 202 285 284 235 289 23 291 295 PIA 297 302 505 50 507 50n NY Sin 511 512 313 315 342 145 344 345 545 547 JAR 349 359 551 152 333 534 555 335 557 558 13 530 381 152 0284 0215 0302 0047 0000 0003 0007 0029 0008 0935 0055 no7n n07n 0010 nonna 00 0 8085 0013 0083 006 0086 0029 0089 0089 Hone Dont 00A4C 0092 0092 0092 0045 09959 0035 00924 0598 0098 0078 0158 009R 0097 Nove 0077 0071 0031 0044 00 0017 00 7 0057 NOAA DOAN AOAD 0040 0059 8095 33 0401 2301 3401 7000 037000 37000 3 800 C3CFn1 C3FDOL C31102 C31502 54502 C34CH2 55902 37 2 23 7402 38102 39202 02
5. CALIBRATION POINTS TO MAKE CALCULATION gt HI BINT ADCNEW 01 1009 B2t zBle11 I3 0CAL 4H1 1 I1 zDCAL CB2 13 RLI CREALCADCNEW MOD 1000 100 0 RETURN REALCIS eCRISREALCIIO END PROCEDURE 4NEWVLV CALCULATES THE REGUIRED CHANGE IN THE VALVE POSITION BASED ON THE CURRENT VALVE PDSITICN4THE SET POINT AND THE THE RESULT IS THE NUMBER OF STEPS 08 TO MOVE THE STEPER BEGIN IF FLOPOS 0 THEN IF FLON 0 THEN BEGIN M CREAL CFLOWD REAL CFLOPOS IF THEN 261 262 265 264 255 256 267 268 259 270 271 212 213 274 275 276 277 278 279 280 281 282 285 284 285 286 287 288 289 873 pos 915 925 929 542 953 975 589 1005 1020 1033 1053 1059 1050 1060 1060 1060 1060 1060 1065 1078 1085 1085 1095 1098 1098 1110 1118 1118 1120 1135 1135 1136 1136 1136 1116 1136 1126 1126 1156 1142 1148 1155 1171 1184 1190 1190 1207 1220 1225 1226 1249 1256 1250 1250 1250 1250 1259 1256 1261 1256 1271 1279 1289 1501 1301 1514 1225 1535 1346 1356 1557 157 1577 1383 4 315 523 23 lt lt THEN MEZI
6. 57 F3 3501 0579 5 0378 3r 4n 0376 c3 F3 38 05 NIT SE91 0578 CROC rs 529000 F1 nf nF DF 320100 Dpn1 F5 EROF 520200 F1 DF OF DF 220709 SO UT MAOFF MI7UTMLSN M JTM10FF M JSTMOYN M JSTMOr M JSEYIN 4 315 523 OUT ot LY OUT 1053 QUT EI Rit LD OUT Lu OUT R T DI LJ DUT EI 01 QUT LO IN PUSH AND 10 ANO RRCA RREA RREA RETA par AND RRCA RREA RRCA RRCA LD coor col t 4 5 CONT 201 t CODE CQ ft 5 204 As A CTCSIC IA CODE 5 A 5 Ar nFH AF NF OHI 5339 4 OF DH CBoreA 40 414 15 515 nirs 0174 08174 01 7 0159 0189 NIFA 01 DIFP 1 020 0202 020 N 0f 0207 0208 0 7 NARR 0209 0203 0200 0210 0211 0211 0211 021 0215 021 0219 0218 021A 0218 021C nain 021 021 05
7. EQU cQ 5 A cave C0 5 40H CSTPOUTI COOL EQ 4 CSTPPOS 5 Cun EQU 4 Ar CSTPPAS 5 CIDE CSTPOUTI 9A 5 STPOUT D A CODE equ 5 AF NZo SU SUEND 5 N7 4503 A 541050 9 SJEND Arf hy A 4 315 523 45 46 0283 F1 POP AF 743 0214 AN nF oY 744 02n6 745 0297 0502 OUT USTPOUT A 746 0249 n 321600 LY 5 74 028C c9 RET 748 749 COUE 750 n2 nn M JSTPDN EQU 2 751 0280 9 321500 02 L5 Ay 5 752 0209 FS PUSH i 753 0261 GDF 754 0285 FEOA 135 0255 2001 JR N7 755 02C7 3 9 had 757 0209 1812 JR STPEN 75B8 FED9 STEP3 cn 9 759 02C0 2004 JR NZ STEPS 150 02 3705 A 761 0291 130A JR STPEND 752 0203 5 STEPS CP 5 763 0214 200 JR N ST P5 164 nan JEG Lo Aas 755 0209 1802 JR STPEND 02nn ZEQA As DAH 767 0200 T 5 LD RIA 768 02707 1 769 022F DF OH 779 0271 OR 171 02F 0502 OUT 5 772 0254 3
8. 233401 4 315 523 STPDN 5 EAU 150001 Eau VLVSTS Eau M LORD NOLIST LTST VECO DOF DEFM VFC DEF NOLIS 15 18080 LT5T AMI NnLTST LTST M OHFSFET JP M STTTN JP M2ADCSTS JP M ADCGO JP DDUT JP M SINSTS JP M SOUTST JP M7SIDIN JP M S1IDCUT M VLV N JP M VLVOFF JP M SOLON Jn M STPOFF JP M STPUP JP M STPDN 34 M JSTPDN M JSTPOFF M JLEDOUT M JVLUSTS CODE EQU STINE RESET CODE t M JRESET CODE M J3E T EN coor M JADCIN CODE EQU M JADCSTS CODE 1 M JaADC 6N M JLEDO JT contr M JSINSTS Cone ERU M JS0UTST 201 M J3IOIN CODE M JSIOD IT CooL M JVLVON ENI M JVLVOFF CIDE FOU t M SOLON CODE Eau M J3 O OFF CODY conr EGJ i M JSTPUP char ERU 5 M JSTPDON CODE 293 3 M Jf M0O0N cane 405 40 405 06 oT 509 310 411 412 415 hl 115 17 918 419 420 421 422 23 12 425 426 427 428 429 430 431 52 333 434 455 436 37 438 358 0023 00113 0025 DOHA noi ONC oone noa 0008 00 poc oor
9. L TM10N L TM10FF L STMON L STMOFF L INTOFF L INTON 124 VSTS RINT 5 1 GOL BINT 1 GBL BINT vers 1 RINT DEFS 1 125 127 128 129 130 151 52 155 154 155 155 157 158 194 145 147 148 149 150 177 178 179 180 181 182 183 184 155 187 188 139 190 LOL La 125 194 195 196 137 138 193 201 04 315 523 729 30 M TII BBE INTEGER 5004 M 11 DEFS 2 GBL INTEGER DONG DEFS 2 GBi INTEGER nnns M DES 2 GBL INTCGER 000A DEFS 2 INTEGER 4243 GBL REAL 2002 GEES 4 MPR E GBL REAL 0010 DETS GBL CHAR 0014 M CI 0275 1 1 M DUMMY GAL PINT 0015 DEFS 1 4 DUMMY TBINTS 2 5 GUL RINT 1015 M STPPOT REIS 1 GBL INTEGER 0017 M TIMES DEFS 2 TI Z INTE r R GBL AINT 0019 1 DEFS 1 TIME1 BINT M STPSI GBL INTEGER M2STPST2 DEFS 2 STPSIZ INTLSER M yVLVPO2S INTEGER 001t M VLUPOS DEFS 2 VLVPOS INTCCER 3 oor DATA INTERMAL LOROM ASSIM LY PROCEDUKE PRCSETIASSEMBLY PROCEDUPE MIEMSETIASSEMRLY PROCEDURE IRINT 5 55 SHINES ADCSET ASSEMHLY 5 MANLY CTCSETZASSEMBL Y STPSETIASSEMBLY 5 TIMERISAS
10. age and thus the diaphragm position is determined as a function of time which allows the flow rate to be calcu lated given a calibration curve of volume versus dia phragm position as shown in FIG 6 The use of a flexible diaphragm as part of a fluid meter is based on our discovery that contrary to expec tation the diaphragm position as a function of volume of fluid in each chamber is predictable and repeatable each cycle despite the fact that the diaphragm is flexible and loose i e the diaphragm is designed to interfere minimally with the fluid flow Thus diaphragm 4 serves to separate the left chamber 126 from the right chamber 12a while supporting magnet 5 the position of which is used to measure the fluid flow rate The cali bration of the position of magnet 5 to the output signals from sensors 6a and 65 is essential to the proper opera tion of this system As is apparent from FIG 1 dia phragm 4 can easily be replaced should it wear out by separating the two halves of cylinder 12 removing the old diaphragm and inserting a new diaphragm cally to ensure a leakproof connection diaphragm 4 has two O rings an inner O ring 210 and an outer O ring 211 as shown in FIG 13 which shows the die used to fabricate the diaphragm It is apparent from the above description that the position of diaphragm 4 as a function of time is directly proportional to the volumetric flow rate of the fluid By knowing the
11. 83 B4 5A LEDOUT STPSET M2M1STRT LODE EQU T coor EQ 4 CONE 00 3 5 4 CTENI CTC2 CODE EDU T AF DE HL HL 7FFFH HL sDE Ht NC4TMORET 340 441 442 443 54 445 46 447 449 450 451 452 453 454 455 455 457 458 459 60 51 452 453 164 455 446 357 ang 09 70 aTi 572 473 474 ATS 475 477 479 580 81 882 433 ana 4A3 85 487 489 499 491 492 493 49 495 4945 397 438 4909 300 501 n 305 504 105 105 207 308 503 310 HO 312 313 513 0119 0113 0110 011 B11F 1120 0121 0123 0125 0122 0124 012 0128 019234 0120 0120 0130 0131 0152 0134 0154 0134 0135 0135 0137 0138 0154 013C 0119 0142 0144 0145 0148 0145 014C 0150 0153 0155 0157 0159 DISA 8125 0152 0155 0157 DIAA 014 0150 170 0172 0174 0171 0173 017 0181 0184 9185 8155 6123 0159 AIRE D1 F 0100 01 31 6192 0154 019 0174 017 37 25 221700 11 FDan F3 rs 34109 3003 3c 321900 1 rn EDAD FR 95 F5 1 1C H5 2095 3 2 1844 7 2024 an 221420 241009 23 2321001 112003 47 3802 531 00 210000 221 00 1808 09702 1825 23 221 00 0882 F
12. more sensing devices to provide measures of the flow rate during the displacement of the diaphragm along the cylinder Signals are generated by the electronic control circuitry for switching a pair of three way valves one valve comprising the input valve and the other valve comprising the output valve such that during one half of a cycle the intput valve transfers fluid into the cylin der on one side of the diaphragm and during the other half of the cycle transfers fluid into the cylinder on the other side of the diaphragm The output valve is switched synchronously with the input valve to trans mit fluid from the other side or one side of the dia phragm to the output valve The electronic control system includes means for ampli fying the output signals from the one or more sensing devices sensors to provide one or more signals rep resenting the position of the diaphragm as a function of time means for converting the output signals from these amplifiers to digital form and computation means for operating on the digitized output signals from the sens ing devices to provide control signals for controlling a second input valve thereby to control the flow rate of the fluid being metered to within a desired range 11 Claims 16 Drawing Figures STEPPING MOTOR DISPLAY TO POWER CONTROL ry ECTRONIC VALVE SUPPLY CONTROL UNIT 0 5 Patent reb 16 1982 Sheet 1 of 10 4 315 523 FIG 2 ELECTRONIC 7 Z
13. 0072 0075 0 0025 OCCB 00658 00648 OCCA DOCB goce 0072 00 5 annA 9 QUE 4 0077 0 DOFO 1 0025 0085 00 75 071 00 5 ANF f Out f 00 17 00 7 BREF OOFF 0101 0103 01995 0107 1 0108 0108 0108 8149 0103 0108 010C D10F 0110 0115 0114 0116 0117 O00 0 35 C35hn501 C 3A001 C3PAQ01 230491 C3F 300 C35F500 C30603 F3 CDF 700 0802 CO A02 347 520016 320100 320200 520300 01502 CDERO2 10000 3208 D37C 5501 DIFE 0370 D376 OSTF FS D5 FS 1700 4 315 523 M2TMaOr 7 JP M TMIDN JP 2 M STMON 25 JP M2INTON JP NO INT OFF J ETVLVSTS d M JRESET DI Ln CAGE CALI CALL LU LO 15 LD LD 19 LD CALL CALL JP gt re MAJINTOFF M CTCS T L OUT DUT OUT QUT RET 21 PUSH PUSH LD PUSH 19 SBC POP JR 36 ris M JINIOFF CIDE c0 M JIMION CODI 204 t M 1M10FF M JSTMON FG 5 M JSTMOFF FOU 5 M JINTON pod t JINTIOFF Cour 5 M JVLVSTS COI 011 SP YF OP ADCSET STOSET 0 CBLIPA 32 4
14. 0224 0225 0321 0224 n22c 022 0 022 02 0 0251 0234 0235 0257 0259 kd 023A 0234 0234 023C 025E 0240 02 2 0343 02 5 0244 0245 0244 8249 D24R o 4 315 523 41 4 JAnCSTS L CPL A7 AND RT 3rni LD REF M JADCIN Lo 2 AF 10 LD 2F rPL 57 LD c9 RET M ADCSET AF KOR CPL 2 10 32F9F0 LO cy RET M JAD CS 2 Li RET MIULEQOIT 340100 10 EGOF AND 07 07 07 RETA 07 RLCA 47 340000 LD r oF ng OR 0300 340300 LD E6n0F AND 07 RLCA 07 RLCA 07 RLCA 07 HLCA 47 LD 34929090 L E6nF AND 0301 OUT C9 RET 2 19 030 OUT 3E09 10 DIDE OuT c9 M JSINSTS 905 LD 640 AND 10 42 cant gt 2 1 tou t Hr A 2007 4 AOCSFLOSA SA CODE EDU A 02 OFH BoA 31 NFH n LEDLOD A CT B 0 1050 coor 55105753 DAVMSK BAS 55 557 56 TO 57 472 573 57 To 519 379 180 551 82 ni
15. 1220 data acquisition board comprises the STD bus a stan dard bus used by Mostek and Pro Log for interconnect ing the components of a typical eight bit microcom puter system using an eight bit microprocessor such as the 780 The operation of the STD bus is described for example in the Pro Log publication copyrighted 1979 entitled Series 7000 STD Bus Technical Manual The operation of this bus is thus well know in the art and will not be described in detail The above cited Pro Log technical manual is incorporated herein by reference Control logic 762 generates several sets of output signals First this logic generates a set of signals for controlling the setting of analog switch 74 These sig nals are transmitted on lead 74 Logic 7 is driven signals taken off the STD bus and generated by mi crocomputer 81 Output latch 76 part of TTL I O Board 83 gener ates a signal to actuate driver circuit 795 which in turn produces signals which operate three way valves 1 and 2 Driver circuit 79 is shown in more detail in FIG 10 and will be described below Additional signals from output latch 766 also actuate driver circuits 796 which in turn drive stepper motor 79c Stepper motor 79 controls the setting of control valve 79d which controls the flow rate though valves 1 and 2 Thus the output of latch 766 derived from mi crocomputer 81 controls the setting of valve 79d in response to the flow rate measured from the
16. 5 mS 4 27 5001 MINIMUM SAMPLE DURATION 45 mS DELMIN 300 800 SPLDLY 20 AVECON 23 C MINe CONST pHa cOoOOcocOocooocoooooocooooooooooooonodoo READING DIFFERENCE FCR ALLOWABLE SAMPLE MAXIMUM VALVE POSITION IN STEPS FROM CLOSED FOR DELAY BEFORE STARTING SAMPLE FOR 1 2 0 Of CONVERSIONS PER READING 4 315 523 17 18 EXTERNAL Deer 2 Geer RESET ASSEMBLY SETIM ASSEMBLY PROCEDURE BINT j ADCIN ASSEMBLY PROCEDURE 2 INTEGER ADCSTS ASSEMBLY PROCEDUREZBOOLEAN ADCGOLASSEMBLY PROCEDURE HINT i LEDOUT ASSEMBLY PROCEDURE 2B INT SINSTS ASSEMBLY PROCECURE BCOLEAN SOUTST ASSEMBLY PROCEDURESBCOLEAN SIOIN ASSEMBLY PROCEDURE CHARS SIOOUTZIASSEMELY PROCEOLREZCHAR VLVON ASSEMBLY PROCEDURE BINTI VLVOFFZ ASSEMBLY PROCEDURE 8 SOLON ASSEMBLY PROCEDURE 2BINT SCLOFF ASSEMBLY PROCEDURE BINT i STPOFF ASSEMBLY PROCEDURE BINT STPUPSASSEMBLY PROCEDURE BINT STPDH ASSEMBLY PROCEDURE SBINTS PROCEDUREZBINT TMOOFFZASSEMBLY PROCEDURE 01313 TM10N ASSEMBLY PROCEDURE BINT TM10FF ASSEMBLY PROCEDURE BINT STMON ASSEMBLY PROCZOURE BINT STMOFF ASSEMBLY PROCEDURE BINT i ASSEMBLY PROCEDU
17. 523 FIG 9 15V SENSOR CIRCUIT 100 1220 0 0 102 DRIVER lg eec _______ __ CIRCUIT d IN4114 i 01 101 WINDING TEPER 1006 7 lt MOTOR W2 WINDING 2 100 STEPER TTL ne DRIVER MOTOR CARD gt 52 CIRCUIT WINDING 3 PORT 2 DRIVER STEPER NDING 4 100a 100 DRIVER SOLENOID CIRCUIT S DRIVER MOTOR amp SOLENOID CIRCUIT DRIVER CIRCUIT SOLENOID 2 FIG 10 255 Sheet 8 of 10 4 315 523 Feb 16 1982 U S Patent 213 110981 1714510 AV 14510 b0 dH 1910 14510 dH 011 914 119919 10481 133 11109819 911310 133 8 110981 2 1131 133 1 0 1109 IT 111 i 710281 10481 11910 U S Patent reb 16 1982 Sheet 9 of 10 4 315 523 PON POWER ON ASSEMBLY JRESET amp STR INITIALIZE LINES 111 118 LINE 121 SWITCH SOLENOIDS CALL 7 ADJUST NEW VLV VALVE YES LINES LINE BEGIN A END OF NEW SAMPLE MS SAMPLE 12 U S Patent Feb 16 1982 Sheet 10 of 10 4 315 523 200 UPPER DIE SECTION 200a INNER 0 RING 210 cc cue O RING 211 2 ELASTONER 12255 2 dem LOWER DIE MATERIAL 7 PB 200b 4 315 523 1 ELECTRONICALLY CONTROLLED FLOW METER AND FLOW CONTROL SYSTEM 1 Field of the Inventio
18. RBIF 022 8075 9034 1280 Oui H 8555 noas 9721 023 DEFY 8597 eer gt 4 315 523 49 50 92 0059 DISI DoF a BASS 95 A123 526 2121 98 9824 027 DEF 4 9371 35 2055 BS25 528 DrFH 9555 25 0050 6225 929 99354 0052 27 010 DEFY 10239 0074 4929 DETH 10559 39 0050 0 52 DEFY 10888 100 0028 BF 035 11193 101 054 11580 102 Hose Fron 035 11751 103 242F 036 2058 104 9050 7030 032 12400 195 0062 9031 038 12701 105 0054 1232 039 DEFY 12814 107 CF3 DANT DE H 13295 LR USS 041 DzFX 15294 10 113 amp 8 5 LOAIMOOULFE TJHMOD Ce Edit 3 51 Date Created THI FER 7 1940 5 5 PM Created TIM T Associated Loadlist 1 311 7 Loadlist Edit 117 700035210633343553537030126013701 0003131323334555657 58394 142434445463251323300 00242 1 09534 5 303758 3941424 344458533515235554353637C 3800 042434 445453431323334F9 7004521003534537383594142935949586333152335435353758394142434445 4536313233343503 730652 107203810 05 L424 34414 34655731525334535 3637393041424 34 44SA 6C 3 00 302016326 008721120002C3F701C31402C31502C 31 5026 34F 92055 3026 35A302C36102C38C02C3A202C3358 7003 321157702 3350205949502 300020337010 38501 SACHIN 00380010 3C70 10 3F 6000
19. SE 5184 an 590 541 592 025 39 505 295 SOT 593 499 700 701 102 103 104 105 705 107 704 109 710 135 135 7357 740 741 02 C 0247 n2 4c n24F 0251 0272 0254 1 12654 no 0255 02 7 5 0950 0278 02 F 0259F Age 0763 0765 0258 1 0262 0259 0269 24 DIRE 0271 0372 027 2278 0274 0217 0229 027 0277 D O27F OP Tr 027F 0242 0746 0285 3 028A 02 OPRA 0280 0291 0292 0292 0292 0297 nau COIR 0234 02 C 0240 0242 2 0249 02 0210 Gone 43 4007 SEDI c9 cg 541400 Hse 341600 0302 321600 ca 541500 E f 3F 521600 5307 c9 341500 321400 n302 c9 1 00 F630 n302 321200 541000 670 502 341600 r5 EROF FE Qf 2004 05 181 FEO 2004 3E09 1894 FECI 2004 1302 SFU 4 315 523 241500 51 LC ANS REY Lu RIT M 2J3IOTN IN RiT M JSIODOUT LD OUT M JVLVUM L Or DUT LD M JVLVOFF Li OUT R M JS5CLOrFF LD AND QUT M J301L9 N LD nuT RET M JSTPOFF Ln AND UT 8 1 M JSTPYP PUSH C JR Lo 48 Sus c Jn LO JR 509 43 LD 48 SA 9 surunn D 44 coor TOJO 5 05 5 ROYYSK 7 1
20. erids of said chamber and for switching the flow of fluid into said chamber from said first subchamber to said second subchamber and for switching the flow of fluid from said chamber from said second subchamber to said first portion 4 Structure as in claim 3 including reference means representing the relationship between the position of said magnet and the volumetric displacement of said diaphragm thereby to enable the determination of the volumetric displacement of said diaphragm from the output signal from said means for producing 5 Structure as in claim 4 including means for varying the position at which the motion of said flexible diaphragm is reversed by determining the flow rate of said fluid and selecting a reversal point to maximize the sensitivity of the output sig nal from said means for producing as a function of the displacement of said flexible diaphragm 6 Structure as in claim 4 including means for reversing the direction of motion of said flexible diaphragm in response to the expiration of a predetermined time 7 Structure as in claim 2 wherein said chamber is cylindrical 8 Structure which comprises a chamber containing two openings therein a flexible diaphragm containing as a part thereof a magnet said diaphragm separating said chamber into a first and a second portion and sealing said first portion from said second portion so as to pre vent leakage of fluid from said first portion to said second portio
21. of diaphragm 4 An important part of the system is the calibration table calibrating the volumetric displace ment of the diaphragm to the output signal from sensor 65 To ensure an accurate conversion of the output signal from sensor 66 into a flow rate the volumetric displacement of the diaphragm 4 represented by any given signal from sensor 65 must be determined accu rately Techniques for doing this are well known One such technique comprises the discharge of a fluid from the output line into a vertical stand pipe in which the discharged fluid or gas displaces a colored liquid By calibrating the stand pipe in terms of milliliters or cubic centimeters for example the volumetric displacement of diaphragm 4 can be measured with great accuracy FIG 6 shows a curve of voltage from sensor 65 versus volumetric displacement of diaphragm 4 While the structure in FIG 7 has been described as using one Hall effect device sensor using two Hall effect devices one on each side of chamber 12 yields twice the sensitivity to the measurement of flow rate By using two Hall effect devices the range of the de vices is doubled The diaphragm 4 can then travel a maximum excursion distance in chamber 12 and during its travel in the left portion of the chamber sensor 6b is used while during its travel in the right portion of cham ber 12 sensor 6a is used In this manner both sensors are operated in their range of maximum sensitivity and thus a sensor
22. of the magnet by the elastomer and excellent control of the diaphragm thickness A Viton diaphragm typically has a durometer of fifty 50 particularly suitable valve for use as valves 1 and 2 FIGS 1 and 7 is the D30 three way valve made by Precision Dynamics Company This valve switches within about eight milliseconds and is fabricated out of 303 and 430 stainless steel with viton elastomer for the seals and O rings Other valves are also appropriate depending on design requirements The flow measurement by this device is reproducable well within one percent Diaphragms or bellows can be easily replaced before fatigue sets in FIGS 2a and 25 show two configurations for the diaphragm inside the cylinder In FIG 2a a diaphragm has a magnet mounted internally to it which is pro tected by the material of the diaphragm The diaphragm is then connected and sealed to the ends of two bellows Each bellows is capable of contracting or expanding in response to lateral movement of the diaphragm in re sponse to fluid entry into one or the other chambers of the cylinder Thus when fluid enters the left chamber of the cylinder the diaphragm and the magnet move to the right and the fluid in the right chamber is expelled When fluid enters the right chamber the magnet and the diaphragm move to the left expelling the fluid in the left chamber magnetic sensor mounted on the cylin der detects the motion of the magnet and thereby pro duces an
23. operating in its maximum range of sensitivity is used over the full travel of the diaphragm 4 The thumbwheel 77 FIGS 7 and 8 is used to place into the system set point which determines the flow rate to be allowed by valve 79d The set point is placed into the thumbwheel The system then measures the difference between a new set point and the old set point program then loops back through the set point change logic and produces an output signal propor tional to the difference between the new set point and the old set point If there is no change in the set point during this loop back the system then looks at a mea sured variable called sampling The concept of sampling means taking a reading calculating a diaphragm displacement from the reading starting a timer within the system measuring the output voltage from sensor 66 and testing to determine whether the minimum change in voltage is greater than a selected value In the preferred embodiment the mini mum voltage change required to be detected from sen sor 66 before a flow rate 15 calculated is 200 millivolts Thus in reading voltage when sampling a sufficient voltage change is allowed to ensure that the minimum voltage change has occurred or a maximum time has elapsed without having this minimum voltage change occur If in this maximum time the system does not record a minimum voltage change DEL MIN the sys 4 315 523 13 tem then assumes zero flow and op
24. pass directly into the output line During the entry of fluid into left chamber 126 dia phragm 4 and magnet 5 move to the right toward Hall effect sensor The output signal from Hall effect sensor 6a is a function of the position of magnet 5 which in turn is proportional as a function of time to the rate of fluid flow through line 9 into left chamber 125 As magnet 5 moves closer to sensor 6a due to the displacement of diaphragm 4 to the right the Hall effect sensor 6a produces an output signal uniquely related to the position of magnet 5 This position as a function of time is a function of the flow rate Sensor 6a produces an output signal which is monitored in a manner to be described later by the electronic control circuits As magnet 5 reaches its rightmost position a control signal is generated switching valves 1 and 2 such that the input gas now flows through line 7 into rightmost chamber 12a while the fluid in leftmost chamber 126 is expelled from this chamber through line 8 and outlet valve 2 Consequently diaphragm 4 is forced to the left and magnet 5 now travels away from Hall effect sensor 6a and toward Hall effect sensor 65 The output voltage from Hall effect sensor 65 is also uniquely related to the 0 20 25 35 45 50 55 60 65 4 position of magnet 5 Since each sensor s output voltage is uniquely related to the position of the diaphragm by measuring time independently the sensor output volt
25. said flexible diaphragm said magnet being formed as an integral part of and being completely enclosed by the material of said flexible diaphragm means for directing fluid whose flow is being mea sured through said first opening into said first sub chamber while withdrawing the fluid whose flow is being measured through said second opening from said second subchamber and in response to a control signal reversing the subchambers into which the fluid is inserted and from which the fluid is withdrawn the movement of fluid into one sub chamber and out of the other subchamber causing said flexible diaphragm to move into the subcham ber from which the fluid is being withdrawn means for producing an output signal representative of the position of said magnet means for converting said output signal to a sequence of digital signals 20 30 35 40 45 50 55 65 H17FFLD52F20D1514z0218EFC9 2 means for processing said sequence of digital signals to produce a second signal representative of the flow rate of said fluid into and out of said chamber means for comparing said flow rate to a reference flow rate to produce a control signal representative of the difference between said measured flow rate and said reference flow rate and means responsive to said control signal for changing the flow rate of said fluid 3 Structure as in claim 2 including means for sensing the approach of said magnet to one or the other
26. some specified time for the lowest expected flow rate In one embodi ment this specified time is on the order of two 2 sec onds This time must be much greater than eight milli seconds the switching time of the valves In describing the operation of the program of this invention certain conventions must be defined Thus in the following description a conversion comprises one look at the voltage produced by sensor 65 reflecting the position of diaphgram 4 The average of four conversions comprises one reading The signal representing the average of these four conversions is a digital signal as is the signal repre senting each conversion Continuous readings are then made of the output signal from sensor 65 on a periodic basis until a change in voltage from 65 in excess of a minimum voltage change DELMIN is obtained At this time the sys tems has completed one sample The system actually takes four conversions at the start of operation and continues taking groups of four conversions and averaging each group of four Since it takes about 25 microseconds for each A D conversion and there are four conversions per reading 100 micro seconds are required at a minimum for one reading After each sample the program tests to determine whether the direction of movement of the diaphragm should be reversed Every seven and one half millisec onds or thereabouts there is an interrupt and for a few microseconds the program then decides
27. structured language for implementing programs on the Z80 This language is written in PASCAL and modeled after PASCAL The Microl compiler pro duces the Z80 assembly language which is assembled and then linked with other modules to form the final object code Microl is a publicly available high level language and is described in a document entitled User s Manual Microl Language Mar 8 1979 This document is herein incorporated by reference Referring to FIG 12 at the start of the program power on reset results in the program going to JRE SET which initializes the processor CPU and timer stepper motor and valve Essentially the program closes the valve and turns off the timer The program then jumps to the main control algorithm represented in the Microl procedure by MISTRT The main control algorithm calls these other Microl procedures to implement the computation of flow or displacement or new valve setting MISTRT and these other Microl procedures call numerous short assembly language procedures to implement low level functions directly on the hardware such as moving the stepper up or down one step or outputting to the display LEDs from a specified register The program includes rou tines for handling two vectored interrupts i e means in the hardware and program for jumping to different locations in memory when the two interrupts occur generated by the timer One interrupt is activated by the timer to keep track of elapsed
28. temperature and the pressure of the fluid the mass flow rate can be determined in a well known manner When sensors and 65 comprise reed switches the output signals from these switches occur with a fre quency directly proportional to the flow rate and are used directly to actuate electronic circuitry for both valve actuation and feedback or other fluid control purposes On the other hand when the output sensors 6a and 6b are Hall effect devices a continuous output signal is generated from each of these sensors This output signal is related to the flow rate By knowing the calibration curve of output signal level versus displace ment of the diaphragm 4 and magnet 5 the volumetric flow rate can be calculated continuously as a function of the output signals from sensors and 66 Diaphragm 4 is preferably made of an elastomeric material viton is preferred but neoprene silicon rubber and butyl rubber can also be used as appropriate which is suitable for use for temperatures up to 150 C 180 C for viton For higher temperatures metal bellows can be used in place of the elastomeric diaphragm The choice of the diaphragm 4 material depends on the particular fluid that is to be used and the preferred operating temperatures The differential pressure across the diaphragm is small in comparison to the working fluid pressures Preferably this pressure difference is negligible Viton is appropriate for temperatures be tween 4
29. the electronic control cir cuitry this description is exemplary only and is not intended to limit the scope of the invention Turning now to FIG 1 a flow chamber 12 contain ing a right chamber 12 and a left chamber 126 sepa rated by diaphragm 4 is shown schematically Dia phragm 4 has mounted on its center as an integral part thereof a magnet 5 Magnet 5 is completely coated with the material of which diaphragm 4 is constructed to protect magnet 5 from the fluid possibly corrosive being metered On the left face of chamber 12 is a sensor 6b and on the right end of chamber 12 is a second sensor If desired only one sensor either or 65 can be used While shown as reed switches preferably these sensors comprise Hall effect devices of the type known as LOHET for linear output Hall effect transducer sensors such as described in more detail in Electronic Design 19 dated Sept 27 1979 on page 23 This article is incorporated herein by reference Other Hall effect sensors can of course also be used with this invention The input flow is transmitted through three way valve 1 shown schematically arranged to allow the flow to pass into line 9 connected directly to left cham ber 125 The entry of fluid into left chamber 125 dis places diaphragm 4 to the right thereby expelling fluid in the right chamber 12a through line 10 Three way outlet valve 2 is in this mode adjusted to allow the fluid flowing from line 10 to
30. time during a sample by incrementing a register or memory location every one half microseconds Another interrupt is activated by the stepper timer which generates an interrupt every 75 milliseconds and vectors to the interrupt servicing pro cedure STIMER to determine from memory location STPSIZ whether to move the stepper motor up or down or not at all Once the program has been initial ized the program checks to determine whether or not the system is sampling If the answer is no the pro gram then checks to determine whether the flow into 5 20 25 35 45 50 55 65 14 chamber 12 should be reversed This test which com prises measuring the output of sensor 65 to determine whether diaphragm 4 has reached its minimum or max inum point of excursion yields either a yes or no If the answer is yes the flow should be reversed The program then initiates the subroutine which switches the solenoids which drive valves 1 and 2 FIGS 1 and 7 through driver circuit 795 and initiates a delay to ensure that the flow has actually reversed and the tran sients in the system have settled before starting to sam ple to measure flow rate during the reverse motion of the diaphragm If the logic indicates there is no need to reverse flow the system then determines whether or not there has been a set point change If yes the valve 79d is adjusted by measuring the difference between the new set point and old set point I
31. whether step per motor 79c should be instructed to step valve 79d in one or another direction Every flow rate calculated from each sample is sent to a memory location called FLOW By comparing the calculated flow rate to the set point placed in thumbwheel 77 FIG 7 using the relationship set point minus flow rate a difference signal is obtained Multiplying this difference signal by some non negative control function gives a gain for use in determining the proper change in position of valve 794 This gain is placed in STPSIZ The non negative function is in turn a function of set point minus flow rate and can also be a function of one or more previous set point minus flow rate measurements separate interrupt program called s timer looks every 73 milliseconds at 0 20 25 30 35 45 55 65 12 STPSIZ to decide whether to step up or to step down the valve In the above calculation the program uses the sub routine GETFLO to calculate the flow Subroutine NEWVLV corresponds to the control function which generates the new valve position STPSIZ corresponds on a one to one basis to the steps on a valve It then takes 7 5 milliseconds for the valve 79d 10 make step The program does not sample while the valve is opening or closing Once sampling is started a sample is always obtained before the direction of motion of diaphragm 4 is re versed and before it is necessary to reverse the motion
32. windings to be energized depend upon the setting of the stepper motor a record of which is recorded in the RAM memory of microcomputer 81 and the direc tion in which it is desired to move the stepper motor The stepper motor will move a standard distance typi cally 1 200 th of a revolution once each step A timer in the microcomputer allows the generation of a new step after a fixed time has elapsed In the embodiment of this invention this time is 7 5 milliseconds The timer on the microcomputer board 81 interfaces with the mi crocomputer central processing unit CPU via inter rupts The timer generates periodically signals which are transmitted to the CPU on a separate line thereby to activate an interrupt circuit within the CPU through an interrupt pin This signal then activates the CPU to calculate the next setting for the stepper motor that is the CPU determines whether the stepper motor should 0 30 40 45 50 55 60 65 10 be driven such that the control valve 794 is either opened or closed based upon the last flow rate reading present in the microcomputer when compared to the thumbwheel setting Typically the stepper motor is driven by a sequence of signals on input leads DO through D3 corresponding to hexadecimal 5 9 6 A Thus if the setting of the stepper motor corresponds to a 9 then the hexadecimal encoded binary 6 transmitted on input leads DO through D3 will activate the stepper motor to m
33. 0 and 180 C and pressures between vac uum and 300 atmospheres The diaphragm with encapsulated magnet is made by a compression or transfer molding process In this pro cess illustrated in FIG 13 a metal die 200 containing upper section 2002 and lower section 2005 is fabricated to the exact dimensions of the diaphragm Die section 2005 includes a central cavity 200c to house the magnet 212 corresponding to magnet 4 in FIG 1 A thin disc of the elastomer material 213 having the same or 4 315 523 5 slightly larger diameter as magnet disc 212 approxi mately inch and preferably formed of Alnico 8 or Cemarium cobalt is first inserted into the magnet cav ity 200c and the magnet 212 is placed on top of this thin disc A pre weighed amount of the elastomer raw mate rial 214 is then put on top of the magnet 212 the mate rial is heated to about 400 when Viton is the material and pressure is applied to it by the upper half 200a of the die 200 to mold and cure the elastomer 214 to the de sired diaphragm shape The pressure is merely that sufficient to achieve the desired result The compression is conducted at an elevated temperature whose magni tude depends on the particular elastomer and results in elastomer material 214 and 213 assuming a substantially uniform thickness typically 0 015 to 0 020 when Viton is the material and consistency throughout the die 200 This operation ensures complete encapsulation
34. 048 477 15 0152510060 31 0DCDOC 1360221173100 1210105006878 2 00985 4 528020 EO 1CB3RCHICCBIDT7DBIGFAE 5212 1 TIF COX BIT 10 5 83804 72C 1900 500F 2 91 21 0 021 52115H7F2FEDASEF CAACSZCOACHZ7A3 7224065A7 155r 30003CA 7237 4 4 4 603510213A0093 D42C8312 2617ED6ACS 310DFD7200F 02B1601CR2 TED6AC9 7B 50502115CIE17DATF25F0DED4 1000 12 1700171 056770 38500728 815 0 10 7007121 1 0 2 12 9C 11 TBF LACA20CHS8501029CO L38FEACA0029CH138FEA 7009221 1 1 1 0 33 35 000CBISCBOBCE 00201 5 65 2 0068 0DR3211F7n38201530CDCB0 H8200CC32C84200 305AC 957C BAR COE RCSE 3DACIE17DDIEICSRA 00D04212187CL 02066CU0 ACORCOF F 7817 300ACG2CCHIOCHIACBIBCBI81F3012CB2CCRIDCBF6 0DF521 2 41ACBISCH2CCBIDChR ACBIRCHI B1F 2022CB CCB1 2 10 1 1 29 9 185821122CCE1DCBIACHIBCRB2CCHIDCHLACHIACHIBIFS0055435A555C611F 30044 4285 169 800 0 5705261000 2 CA APA 33CCO 10000 545009775 E45nr2 n46 TEOC ECC AE S4 675 9 55 5211 7C7410A782425 1 4604 7T 7 RCB82DCG1AT1F10 911 0ZT D11C FFD197nA9FDE5210500 A92J6L 1204 AFEO A70 B142 BFEE2890EEBIF
35. 0E95201ECS6F 7C 8205 7TEAECDAAFRGCHFELAF2B8AQ0ET18CSOSFD 550524 44DE 1E RC9F 2 0EB50523ATO0F AF 85 95 0 ECHUA0526AF ASCE 11000219411 114001 D5321FF2127FFCB865110000ED5325FF2128FF 3600F D5896 102121071 FD5432nFFCDRFG05215FF CU500532 1L 21271 FCUA62851CC5111A 7116400 008 1042210A52FA65510230nD0A TE BE D5 22FFEEDS2F 255101H11 721204 EF OS APFFFFOS2F 265101808 10532102021 D45CD9C112231FFCOAA12221AFFCD3JD133215FFCDB 003215FFCD38145215F 7 D9 1084200 212 7777485115507 21352157 FEO561AT r 7AU32050 0C20032 1SFF111400z2D55n05 10A52011h FFCDFT1A3215FFCDD81422D04FF 110000ED5 517FFCDBR152205FF2ADAFFEDSBDS 10Ca211405FF123E02CD4509222 5 323F 2 CD3712 D5320F F2228FFCDAACOS215FF21F1 10E5211727FFCBC C 33310C0CO0B3003215F CFSET173F57215400CO 3R082225F F 110521085F179F57210A0DCD5RO3L0SH25FF 192225FF 3AQQOFFSF179F57192225FFAT11000080 1127210 F052F A3411A472425FF 117 50522527 23411181 22100FF3G0F 2101FF360E 003298 114A 11115FF 1HA12A25FFCOCO9C UBR152208FFEUGH17FFCLD532FFFCDOB142206FF2ADAFFED2F 1106920155 193 2 5 922 37FFATEDSR2 FFED322208FFAT110000EDS2F29T113A8B 1183211508F2FCF SAQOFFE2ES 0 37127 D5333FF2235FF444DDSF 023 1 12078230 F DAZ BEF 0 30 310 20 1 20 311ZD5BLOFF2AL12FFCDIF Y1CADILHALOAFDSS510FF2212FFED3B2F7F 7AH5
36. 22027110100F D352FFFEDSBIOFF2A12FFFO21ES 11 58211756565017007CD6 30A SDS D5B FFF 1CICDAFOCEDS30CFF220EFFCDA 30D26 12052112 705231FF AT 8110002F052F21212c055 31FFA 7210F 270 D5431FFED52F23212110F 122021152 5 1 1309705200 3C3201FF5ADU0FFS21EFFCDOO 1257211500042203FF 3AD1FF 321 77C20005A77 72 522204 2 37 116800 09709 5 125F21165 D1 0844 005rF OF 11106002154507COc 3JCEF 220FEFFEDRROSFFCDIADBESDAhES 71290700 5 804 19408 7 392AFDE1CICOSA0ECOC9AT210000E DSBID 1230211120FF 052 721C134 2100097 058A31 F E 2F21C12C01408RC 5DSF D582CFFCD1408 201 12 121187 1E 1008 005619 1 2221772210005 14002 05 39EF2FR12110000EDS5J1FFF11A1 12 F 21174202 ED5 321FFEDSBT1FFF2OA217FF221065 60165 0 07 3DBFFA1C13280E116656E05 50 41312210 1FFIL1155F2FD05321F FC D10A7 0580 1 2220 5F FE 4 22 CCFF 1133421074 44 0 5 205 1 1 SCACD 190 8505 6 115 52 258813 034 1 352 0108 396 2427 26C1 S116 8004 DG 305FF2A DFFEDSBOSFF 1 92207 11575211 52 00092 05272841500 332026 47212075 05820 052 7249813112003 05388 159652 0152 Ana FFC9C947219000 EDS 33 72000 1117001922 4 153H521181AFF2128FF3601A72ALAFF
37. 370 00 71711773066 3090 331FFFFCOFADOCOD402CU 5002300087505 3200FF 3201FF 3202FF OR 2 5 3CU 32080 7 57 37 3F555759AT1TFFE511FF 7F A77 D52 139042 32217FFF1D01F1FBEDADF3F53A19FFFE23 012 21127 50043 3219FFF lr 5955 52ALArFFTCUS2005CDa502184BCU7C20 242B227C 014D21151AFF2ALCFF23221CFF112003ATED5233 0CED3 3ICFF 2100002214FF18D8CD95021803 7016 2118232322 1AFFD302E50122082100002214PF221CFF18RE2AICFF 7 528 28221 70185 2111 00002 191 1 405 85037 IL CD37CFHCOF 33703137C 2 D1D37 CF BC9 3E 850370253 D1R0210F SE ACO STOP BCIF 3D3TDF BCOSE ASO STESE 4 HD37EFBCOF 33E O3D3 TESEO103TFFB 42 01012112C9nh00 F 5F5nF 3200FFF1Z BF OOF OF OF OF 320 1F FOROLF SF 6OF 3202FFFLEGFOOFOFOFEF 01F221150F3202FFC9 3AFHFO2FATCRSFDICSSAFCFU2FAF SAF DF O2FG7COAF2F 32FFFOS2F9F02D 02132105C932FAFDC95ADIFFEGOF07070707473AD00FFESAnF B0n3003A03FFEG60F 07070707ATAE 4923421 OF 950 02n5203220003J 2C934A2000 540C233ED1C93A0D00E6B80CAK D 1025902107 3En1C9D20CCOSAl FFDSDCCOSATSFFFA50035025216FF CIAL 6FFE 6 3F 2216FFD30208 12752011 5 16 32102 70 5020 16FFF3003023218FFCO3ALGFFES700302C93AnB 0292 1416 20045 05181 2 052005 32091 MOA 7092004 3104180236054 7F 180 1287211 7 02 21
38. 521400 to 773 0 C9 RET 114 775 0273 CONE 775 OPFR M2STPSET 117 0298 LD 0 173 BIA n302 OUT CSTPOUT vA 779 02 0 321500 L 5 180 02 21 LD HL 1490 781 8262 D 221 00 Le STPSTZ HL 782 02 5 219 05 LO 1 1500 785 0258 221700 LD VLVPOS TRA 0228 C COBAGL CALL STMON 135 02 D 2 1 00 STPSIO LD HL 0501 Lo 737 0502 85 OR L TAR 0303 20 48 N7 STPST 139 0305 RIT 790 DO 630 CODE 123 050 M JVLVSTS 45 n30f nun IN STATIN 194 2308 601 AND 01 195 0 5024 t3 Rit END 3804 COUNT N PU 3 3 58 1 CORA gm gC oda 2 MODULE 3 5 3 C dit 9 4 7 Created TIM Date Last Edited THU FEB 1980 5 44 ro Last Edited i Date Last Compiled Assembled THUs 7 1980 5247 s Last Compilod Assenbled TIM 13 LIST 1 15 La 17 18 13 20 21 22 24 2 24 25 27 23 29 30 51 53 34 55 58 39 40 1 2 45 44 4H 49 50 51 52 54 54 42 96 57 58 59 50 61 52 65 56 57 88 39 91 4 315 523 47 FRAN gL a nnno MITUSTL 5 MODULE Fdit BR f gt gt ok Created Date Last Fdited 7 1980 5144 PM Last Ydited Date Last 11
39. 55502C220 JIF BEC IF ALTON 050 9 IETF 571 0315211 57TACAE 1 001 1E CO LSU 0 05 207407 38312119802524CH13BFE2570B1F CPL BCHLCoE 5 STC NOC 4 2590809975752 DE 4582014C9473274 8H253013C04 05280 TC B20C3H 1349107 2556A 2404 7C LT 924 25 0487I2211UEA 0 53L 1794 2HAQSADQC S 5DA2 76r 759 31094 1735459 3 00 4F 2 1 910 52808 TATFEDA AC HEDA amp ACOFA SIBDABALIOCNNAOBFICLOCLRIFCSFACRFECUCODSONF LULL 14 F7DRONG2 000947 892007 184 0200 JOACIOLISAF 1P03CEA02080 SCC FOCHFC 7052H5F 72400418 42 004AF FUEL 9 2C 1 21802 5 12B85CHHFPAF20ADCCOSFDOCFISCCBFFFSF 127 0002 211 CFDESFD2109007D372109200112000 SE 0 987 0 80015 8150814 13 81290 0C2C211D0 F SMALLER CTA CE OSPF BE SF DGACB13CB12C620D22C0C29 9CAD2120ETCHLACHI 35F 32099457 56 00966708 gC6U0121C91 5 0C6F212 5AFBDn20noAFCOB3 20055ISFAFSCC9TD6C 504 7E SF DESF TA9F5FSFD210500FD3970ECOS5 0C230211 14A57C57C2R1CAF 32573E003065F 5E 02 ICS 7TE2H830CFD 3 400E 2D 10CF IF1F 1C AECOADS 1059121172540 300 92 1F SE 6
40. 64 34552011 41 THU FER 7 1980 Last Comptiecd aAssemybed we me 4 2 1 0000 3 CONSTANT 0029 2 41 1 5413 090 DATA GLOBAL GBL RINT 0000 DFF 5 1 M DCAI RL L DCAL D DCALZASSEMBLY PROCCOUPICTNYEX BINTOIIMTUGCR 1 2 NOUTST 61167 0000 509 M 71NC AL anza ERU D 5 0000 0005 1 nans 3402 R nna 3 09 19 0019 ADD 0003 oF Lo aA 1460 LD D 7 0000 C 211600 HL sOTABLE not 19 ADD HL DE 0011 LO Ar CHL 0012 23 TNC HL 0015 56 LO He CHL 0013 6F LG 001 cC RET 0016 DTA LF 5 00125 08000 0018 Donn n1 DEF 0000 0014 4370 DEF a 101 801 8303 03 039 1 S40 047 DEFR 1420 0020 n ooo 2025 0022 2504 25 DO 2597 0024 5 0C D7 3151 0025 3654 0028 1119 03 DEFY 5113 002 011 010 DEFY 4523 002 011 DUF N 342 00 F 6014 012 DEFN 5216 0030 t015 215 3363 0022 0117 014 5889 0054 2218 015 OCF 6191 01056 931 016 DELER 54647 0058 S314 011 DEFY 6733 COLA 5818 018 DEFW 7000 002 541 0192 DEFY 7292 0055 9010 020 DEFN 7515 0040 TRIE 021 OCF 7798 0042
41. 72005 AF TF A 1 77 1 7 5 70 92 DA44 CBTC2 80 6AF39SAF SF 94 GTAFOLOFEDGALIADIA 0935H2110045F0930n00F2670 ED ACH722802ED4543770H72 00 58AFER0230CCB7 A2BO S AF9SSFE2 93RC2120 F2 657BF COCB7A20F AAF COR BAF 9258D052002AFC90600AA17CB107A17CRIOCBTCODFF 09A0202206AT956fF F3457C47 A2 89 SF 3 93577844402 6006 87 81300812 6 0903 8 9 021250109 89 8135 12 45061002 8098781 8104 TLF 956 9 946 720 AF F30F 9F 9251 1 04 AFDES50141 0527430013645 17042 7935 7894577806 4 315 523 51 52 PYASOPLIA ODE PRICK UGE 75 00996 gt 5 XE24E ALCDAPCCORI FO DPOF SNC GIP 2 222 85F 7884 3TE2 O 5210090020819 11021389 JFCBI1CCBIOCHAS gt 8210405 24D0A2A7105299160215238F E2BE FURR 521 1 7 5730405 CCH1 9300 TAF AOE DE 9 3C 1 1 ODF OAPLEP ASO SCIP 4 AF R 55B8C92452 5F DFEOATD2F 5 267 C92190205
42. 777 MONITOR A DISPLAY AY ABE AN QR SU ELECTRICAL MAGNET SIGNAL SENSOR PRESSURE BALANCE PORT FIG 2 0 5 Patent Feb 16 1982 Sheet 2 of 10 4 315 523 2 STEPPING MOTOR 0 5 Patent Feb 16 1982 Sheet 3 of 10 4 315 523 TO SOLENOIDS 0 5 Patent Feb 16 1982 Sheet 4 of 10 4 315 523 VOLTAGE UPPER REVERSAL POINT 200 0 2113876353242 32 MAGNET AT VOLUME LOWER WALL DISPLACEMENT CM REVERSAL POINT FIG 6 m 4 315 523 Sheet 5 of 10 0 5 Patent reb 16 1982 1914 FW VI TI ERUR 141480 omn 01548 131140 em Bem 01042105 amva Pm M NOT 0 0 V 3416 jj ID 2257 153113 2 1 TWH WNI 29 13 9 ns Be ow 04 08 u3WIL fd c 1 18 08808 NOILISINOW VIVO 8 914 9 39018 59140419313 141101084 331104140 013 4 315 523 33131311 Sheet 6 of 10 110981 105815 Feb 16 1982 193130 0837 301VA 7 14510 0 5 Patent U S Patent reb 16 1982 Sheet 7 of 10 4 315
43. 82 STATIN 2 214 FOFC ADCLO 215 ANCHE En 0F U0 OH 215 Foi V ADCEOC EUY NF QF HH 217 AOCSELY 219 5 01 OF OY SH 219 FOFA ADCCON OF NF AH 220 SIOCON Eau 221 SIOSC 222 0090 510515 EAU 225 onee 10041 509 NOCH 224 ooru hAVKSK EQ 225 RDYMSK EQJ HOH 225 7 crea ICH 227 E DU 228 007F E QU 227 007F CICS ENU 230 0002 Eau 231 0085 EOJ A3H 232 CTCSFN DASH 235 0321 CT RES EUU 03H 34 0001 CTCOIS 255 Creme Tuy 16 235 OCH CICSTC 15 37 0720 VLVPMAX EOY 800 258 0000 259 0000 M MEMSET 240 Fron DSTART EQ 2 1 342 H1 0 MBI 0501 en 4232 0012 45 0003 FOU MIRY 246 11 M II 247 ngan 12 QU M I2 248 0005 I3 FQU 249 0024 I Eau M I 250 00 R1 Enu M PL 251 0010 R2 cau M R gt 252 001 cau M CL 255 0015 LEOU M20UMMY 254 0019 STPPO Lau 5 245 not7 TINEO EQU 2556 1219 TINIG M TIMFE 257 001A STPSI7 ENU M SIPSI 258 001C VLVPOS M VLVPOS 253 260 900 Cop 5 2h1 0070 EQU M RESET 262 0108
44. HLY PROCEDURE BINT M VLVOFF VLVOFFIASSS PROCEDURE HINT i 25210 22 SOLON ASSEMHLY M2S0LOFF i SOLOFFTASSYMBLY PROCEDURE Zu INT j M STPOFF STPOFF PROCEDURE HINTS PHOCEDUREZHINT 22 SIPONIASSLMHLY 81 M TMOONK TMOONIASSEMPLY PROCZDURFIBINT TMOOFFIASSEMBLY PROCEDURESSINTS M2TMLOH TMLONZASSEMULY PROCEDURES M2TMLOFF TMIOFF ASSCMBLY SINT M STMOMN STMON ASSFMBLY PROCEDUREZBINT M STMD SSEMRLY PROCEDURE M7 INTOF i INTOFF ASSCMBLY PROCEDURE BINT M INTON INTON ASSEMBLY PROCEDUREZRBINT VLVSTS ASSEHRLY PROCEDURE 2ROOLE 50017151 gt 3 STMOFFZ es at M n1 M B1 M H3 H R4 0003 22 RL 2 0090 0001 nno BL GBL 3 GBL G BL GAL GBL NAG GBI ANG GHI 6 BL GAL GBL GBL GBE GBL GBL SBL GBL BL G BL GHI BBL GBL GRL GBE ANS GAL 28 5141 PM FER 1980 L MISTRT 1 PRESET L SETIN L ADCIN L ADCSTS L ADCGO L LFDOUT L SINSTS 1250 5 7 2510007 L VLVON L VLVOFF L 50LO0N 12501 L STPOFF L STPUP 5 L 2TMgQON L TMOOFF
45. L MIN logic determines that the difference in the output signal from sensor 65 is less than the minimum required a test is run to determine if the time between this sample and the previous sample is greater than the maximum time If the answer is yes then a new flow rate is calculated and the auto range is adjusted as in the pre ceding sequence If the answer is no then the system tests to determine if there has been a set point change If the answer is yes the valve is adjusted as described above If the answer is no the system loops back to run another test to determine if the new sampling volt age is greater than DELMIN The particular lines on the flow sample in the mi crocomplier version of the program shown in Appendix A which implement the particular logic block in FIG 12 are shown on FIG 12 Appendix B gives the assembly language procedures called for by the Microl procedures in Appendix A As a feature of this invention for applications not requiring the precision and versatility of computer con trolled logic circuitry several lower cost embodiments are possible using either the reed switches or the Hall effect devices A multiple segment down counter can approximate the flow rate by counting down from a 4 315 523 15 maximum flow between flow reversals The rate of down counting is varied after a time interval lapses the device will count slower after each elapsed interval By this method the functi
46. N I2 zSETSET FLOU 1 120 12 1 1 5 IF 12 lt 200 THEN I2 200 IF 122200 THEN 1222200 2 5 5 12 IF FLGPOS 0 THEN 10 05 05 IF FLOPOSSVLVMAX THEN FLOPOSZ VLVMAX RETURN CI2 1 END PROCEOURE FIXUP 24 ALTERS THE NUMBER OF STEPS SENT TO THE STEPER TO ACCOUNT FOR THE SLOP IN COUPLING WHEN CHANGING DIRECTIONS o BEGIN IF STPSIZ 0 THEN IF CIR O0dN THEN BEGIN 5 5 2 5 512 510 DIR UP END IF STPSIZ lt 0 THEN IF CIR UP THEN BEGIN 5 5121 5 512 5 0 DIR zOCWN END 1 END PROCEDURE REVCHK CHECKS TO SEE IF THE FLOM SHOULD BE REVERSED HASED ON THE CURRENT VALUE OF ADCMIN AND ADCMAX IF 50 IT PERFORMS THE REVERSAL 1085 A SHORT DELAY FOR STAHILITY BEGIN DUMMYIZINTOFF lt DIY 2 DUMMY ZINTON IF I4 5ADCMAX THEN DUMMY z SOLON REPEAT IF ACCAVE lt 50 THEN EXIT IF 14 THEN DUMMY S SOLOFF REPEAT IF gt 30 THEN EXIT CNDG PROCEDUPF FLOOUT FLOCUT TAKES THE CURRENT VALUE CF THE FLOW IT TO THE LED DISPLAY BEGIN B1 0EH R2 0tHj 0 11 71 11350 THEN I1 10000 THEN BEGIN B1 RINT CI1 MOD 109 11 11 CIV 10 B2 BINTCI MOD 10 i 11 11 DIV 10 MOD 10 11 11 DIV 10 2 81 1 MOD 1031 END D
47. OCEDURE ZBINTs PROCEDURE INTEGER MIREAL CURRENT dCVALVED dCFLOMW1 ACCOLO INTEGER REAJING AT START OF SAMPLE INTEGERS CURRENT SETPCIAT SAMPLE BOOLEAN 5 FLAG SET WHILE TAKING SAMPLE 4 DIRECTION VALVE LAST MOVED 49 DSPOLDIREALi 4 DISPLACEMENT AT BEGINNING OF SAMPLE 109 110 111 112 113 114 115 144 145 146 147 148 149 150 151 152 155 15 155 156 157 158 159 160 151 162 163 164 165 166 167 168 169 170 171 172 175 174 175 175 177 178 173 180 181 182 183 184 14 16 18 2 26 28 28 28 28 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ec 21 34 at 46 54 50 G6 66 65 74 74 89 co 00 06 12 15 15 28 28 34 40 45 43 51 57 75 87 4 315 523 19 20 FLOPOS INTEGER VLVPOS FIXED TO ACCOUNT FOR SLOP TIME INTEGER i aT IME FROM PEGINNING OF SAMPLE FLOW INTEZGER CALCULATED FLOWs AL C DISPLACMENT DF LATEST ACCNEU INTEGE 5 ALATEST ADC REACING ADCMIN INHTEGE LATEST LOW REVERSAL POINT
48. RE zB INT 5 INTOFF ASSEMBLY PROCEDURE BINT VLVSTS ASSEMHLY DCAL ASSEMBLY PROCEDURE CINDEXZBRINTO INTEGER i B1 82 4B 5 B4 BINT SCRATCH PAD 8 INTEGERS 11 12 13 14 INTEGER 4SCRATCH PAD 16 INTEGERS RI R2IREAL SCRATCH PAD FLOATING POINT 05 4 DUMMY BINT BYTE BUCKET E STPPOS BINT 48115 0 3 STEPER WINDING ENERGIZ ATION PATERN 1 08 5 4 5 ARE 501 12 CN OFFe 1 0N INTEGER ELAPSED TIME KEPT TIMER 0 4 TIME1 8INT ELASPED KEPT BY TIMER 1 STPSIZ INTEGER THIS LOCATION CAN BE LOADED WITH THE NO OF STEPS DESIRED TO MOVE THE STEPER IT IS UPOATED AFTER EACH STEP BY THE STEPER TIMER ROUTINE THUS ANY TIME IT SHOWS THE OF STEPS REMAINING TO COMPLETED BEFORE THE STEPER IS AT THE DESIRED LCCATION VLVPOS INTEGER CURRENT VALVE POSITION GLOBAL MISTRT PROCEDURE IBINT INTERNAL cOcOOcoO0o0o0OQoOocnuOcOodocoooonoooogogooocoagooodocoooooooooogocooooodngoooooooooooooocooooocoooooo GETSET gt PROCEDURE CELTASPROCEOURE 2 INTEGER INTEGER NEHVLV PROCEDURE INTEGER FIXUPTPROCEDURE 2BINT 5 PROCELURE FLOOUT PROCEDURE DISP PROCEDURES ADCAVE PROCEDURES INTEGER DELAY PR
49. SZMBLY STIMERZASSEMALY JAP SETIASSOMALY PROCEDURE ZHINT3 PROCS OURL PROCEDURE SENT PROCEDURE PROCTDUREZIBINF PROCEDURE 24113 PROCEDURF 13 INT 1 me 4 M 24 4 an as 4 we me d 4 2 E a 9 45 ASS MiLY P2SCENURE WENT JANCINIASSEMBLY PROCEDURFIINTEGEMP 5 5 MALY PROCEDURE 900LZA45 JAUCSO ASSLPULY PROCEDURE JLEDOUT ASSEMALY PROCEDUREZGINI JSUNSTSIASS MULY PROCEDURE 3001 JSOUTSTIASSEMHLY PROCEDURE ICOLE AN JSTOIN ASZLMBLY PROCEDURE JSTNOUTIASS PROCEQURE JVLVON ASSEUPLY PRO CEDUARETAINES PROICEDUIPEZ J50LON AS5S IDhLY PAOCEJURT ISAT JSULDFFIASSFMRLY PROCEDURE TNT PROCEDURE ISINTS STPUPIASSFMBLY PROCEDUREISINT JS5TPONIASSEHBLY PROCEDURE HINT 5 MALY PROCEDURE IHINT UPUQOFFIASSFE MALY JTIMIONIASSLMHLY PROCEDURE IBINT JTMIOFEPFIASSLMHLY PHOCED RLIHINT JSTUVONTASSFMBLY PROCEDURE HINTS JSTMOFF ASSFMBLY PROCEDURE ININTS JINTOPFSASSEMNLY PEROCEDUREZBINTI JINTONTASSEMBLY PROCEDUREIBENT3 M 4 315 523 31 DU JVLVZTS ASS MILY PROCEOURFE 211001 ANG 202 2045 1 204 NOLTST 201 LIST 208 0000 SLTLO 0 203 0071 SFTHI 9 1 210 0208 Eau 0 211 0081 tou t 212 9002 STPOUT 800 2 213 00
50. T110000 D32F2F 10 33 01201 1 1 1170693 ONO POLAF FE 3600096 8 00521977003 8141 56 7081401193 02 04 5092280 01 00 3215FF 1 15B02ED3 3DAFFAT21ACO D 0589 052221914 0440032 9 1141172 1101 6 7145215 F A72 AQAFF11F 40I1F D52F 25114CDA I0 D321SFFCDF7145215FFC3DD 155821122100FFALGDE2101FF 356072102FF 38 31FFED S 524F FATE BLING 00ED5 F 11485 1559 115472A045FF111027E252 72231132404FF 11 0A400CD9709783200FF ABA FF 3EDACD450944 4 315 523 53 54 1297097835201 22 04 1 45919220422 1104000097 0978 3289 7143 2 11 50922 1 0 78 3279 VRE COME 0652153220921 OOF F BF 414HB8211E 3505110000 93 AFFCDRCODSDISFFCO39D0C HA72B80218021AF50CD8600E DSAOAFF AA 7Zi14Dnc 0nenis220AFF2100FF 35200213021 BDAD 5E 24CU4502220AFF C90C9110000 605370D ALOFCLAISLTIFFATOAQAFFERS 1300003030 32802017 7 10177000 We claim 1 Structure comprising a chamber containing a first and a O opening through which fluid can pass a flexible diaphragm located in said chamber so as to divide said chamber into two portions a first ber accessed through said first opening and a sec ond portion being accessed through said second opening a magnet attached to said flexible diaphragm means for directin
51. UMMY zLEDOUT END AND OUTPUTS 4 315 523 25 26 337 1384 0 338 1384 0 339 1384 0 PROCEDURE 340 1184 0 ADCAVE TAKES AVECON CONVERSIONS AVERAGES THEM TO 341 1384 0 REDUCE ERROR ANO NOISE 342 1384 0 BEGIN 343 1392 9 344 1397 0 14 0 345 1404 0 345 1404 0 BESIN 347 1404 0 DUMMY zADCGO 348 1410 0 343 1410 0 ADCSTS THEN EXIT 350 1423 0 15 IA4 ADCIN 351 1434 0 IF DECZCH1 THEN EXIT 352 1454 0 END 353 1446 0 14 14 DIV AVECON 354 1857 6 RETURN 1 355 1459 0 END 355 1451 0 357 1461 0 358 1451 0 PROCEDURE DELAY 359 1861 0 C DELAY IS DELAY LOOP WHICH DELAYS 1172 MILLISECONDS 350 1461 0 REGIN 361 1453 0 1 0 014 362 1470 0 REPEAT 363 1470 0 IF TIMZO gt T1 THEN EXIT 364 1488 0 END 365 1485 0 365 1485 0 gt 287 1489 0 PROCEDURE NEWMIN 368 1489 0 NEWMIN CALCULATES NEW REVERSAL FOINT BASED ON THE 369 1889 0 CURRENT 370 1489 0 371 1495 0 4 372 1515 0 ACCMINDMINMAX THEN 373 1536 0 IF lt THEN ADCMINI MINMING 374 1552 0 END 375 1553 0 375 1553 0 377 1553 0 378 1553 0 379 1553 0 ERROR COUNT APPENDIX B RELOCATABLE ASSEMBLER VERSION 2 3 THU 7 19804 5 42 PM ERR ADDR 1 Co e 2 MODULE TJBAL 3 3 Edit 9 4 5 4
52. United States Patent Mahawili et al 54 ELECTRONICALLY CONTROLLED FLOW METER AND FLOW CONTROL SYSTEM Imad Mahawili Sunnyvale Timothy J Boyle Cupertino both of Calif 75 Inventors American Flow Systems Inc Sunnyvale Calif 2 Appl 127 918 73 Assignee 22 Filed Mar 6 1980 531 dete GOIF 3 20 152 44 55 42 55 137 486 137 487 5 73 269 58 Field of Search 137 486 487 5 73 269 73 270 271 56 References Cited U S PATENT DOCUMENTS 287 587 10 1883 Spooner 73 270 3 181 360 5 1965 Hederborst 2e 73 270 3 906 793 9 1975 Wurzbacher 73 269 4 067 239 1 1978 Arvisenet 73 270 4 134 423 1 1979 Mayer 137 486 Primary Examiner Alan Cohan Attorney Agent or Firm Alan H MacPherson Steven Caserza 57 ABSTRACT A novel low friction low inertia flexible diaphragm containing a magnet formed as an integral part of the diaphragm is mounted in a chamber preferably cylin 6b DIAPHRAGM HOUSING 3 WAY VALVE 11 4 315 523 45 16 1982 drical The chamber comprises part of the flow meter in a flow control system One or more sensing devices are mounted on the walls of the chamber to sense the instantaneous position of the diaphragm A novel elec tronic control circuit processes the data from the one or
53. an 2008 2190100 221400 221700 183 1 00 7C BS EREE 2R 221007 281 21 Fl ED D SPRY 0570 4 315 523 INC LE pop PUSH LD CP INC LH RETI Lp OUT 38 HI TIMEN 4 HL Ht t AP CT TMET NC COD FOH t DE HL HL CSTPZT7 AsH N7ySTCKRP M JSTPOFF STM cT Tat NZ STHPHN CSTPSIZ HL HL s CULVPOS HL VLVPOSI HL VLVMAX HL HL 3 5 5 2 STM M JS3TPUP STMRET HL 5 2 STATIN N 7 535TMDN 2 CSTPSIZ 5 HL 1 5 STH HE CVLVPOS L 7 STMDNI HL VLVPOSD4 HL M USTPON Hi DF EQ t CfC 0334 01 18 01 4 013 0197 0197 0198 01 F Dier 0153 0145 0147 OLAS 0159 01349 0149 0140 OV 0191 nis 0173 1185 DIRS 0114 01865 0188 0189 01083 DIRA DPA 0100 01 0105 3 01 0104 0163 01025 01 7 nics 01 DIC 01 1 OCF 0101 nino 0124 nro 015 0104 uitr D1nC 0157 aire niri 01 01 21 n1FA 1 AIFF 0180 n 39 957 C9 3215 D3I7N 0371
54. e flexible diaphragm 4 with magnet 5 formed as an integral part thereof FIG 7 shows in block diagram form the electronic control circuitry used to process the information pro duced by the sensor 66 attached to chamber 12 contain ing the flexible diaphragm 4 used to measure flow rates in accordance with the invention The output signal from Hall effect sensor 65 is transmitted through sensor interface circuit 73 to analog switch 74 Analog switch 74 comprises in one embodiment a well known device for selecting a particular signal path in response to digi tal input signals input to switch 74 on lines 74a from control logic 76 for the purpose of passing a selected signal from either a pressure transducer 72a and a tem perature transducer 72b for the purpose for allowing the mass flow rate to be calculated from the volumetric information produced from the signal generated by sensor 65 attached to flow meter chamber 12 or from sensor interface circuit 73 The output signal from analog switch 74 is transmit ted to an analog to digital converter 75 of well known construction Preferably this converter comprises a 15 25 35 45 50 55 65 8 twelve bit converter such as is used with the Analog Devices RTI 1220 Data Acquisition Board 84 FIGS 7 and 8 The output signal from A to D converter 75 comprises a digital signal representing any one of 4 096 possible signal levels Of course by selecting an A to D converter con
55. e thereby to control the flow rate of the fluid being metered to within a desired range As a feature of the invention an output flow rate is not determined unless and until the diaphragm has trav eled a selected distance or until a maximum time has elapsed thereby to ensure that a minimum volume of fluid has entered the positive displacement flow meter portion of the control system and displaced the dia phragm at least a selected amount By dividing this displacement by the time over which it occurs the volumetric flow rate is obtained DESCRIPTION OF THE DRAWINGS FIG 1 illustrates schematically the chamber in which is located the positive displacement diaphragm used for measuring flow rate FIGS 2a and 26 show diaphragms connected to the chamber by bellows and an O ring type seal respec tively FIG 3 shows schematically the connection of the sensing element on the end of the chamber containing the diaphragm through an electronic controller to an electronically controlled valve for maintaining the proper fluid flow FIG 4 shows schematically the relationship of the diaphragm flow chamber sensing elements the mi crocomputer used to compute the control signals used to control the fluid flow rate the fluid control valve and the structure for controlling the fluid flow into the flow chamber FIG 5a shows the reed switch flow reversal control circuit useful with this invention FIG 55 shows a circuit useful with the circ
56. ens valve 794 7 If the proper minimum voltage change DELMIN is obtained the system then takes the measured voltage from sensor 6b and refers to the proper place on the voltage displacement calibration curve FIG 6 to cal culate the displacement change over time From the displacement change over time and the time the aver age flow rate over this time is calculated Referring now to the calibration curve FIG 6 it is apparent that as the flow rate becomes lower the displacement in a given time becomes less and the reversal point on the curve must move from right to left That is the dia phragm travels a smaller distance in a given time for a low flow rate than for a high flow rate and thus to maximize the sensitivity of voltage versus displacement one must operate on the left most portion of the curve rather than on the flatter right portion of the curve The right most farthest from sensor 65 reversal point is selected to ensure that magnet 5 does not hit the wall and that there is time to generate a voltage change equal to DELMIN between the reversal point and the wall The reversal point closest to sensor 65 is selected by a formula Ci flowx C where C and C are selected constants equal to 3800 and 5 respectively in the pro gram of Appendices and B The logic flow diagram shown in FIG 12 describes the logic of the software program shown in Appendices A and B The program is implemented in Microl a block
57. esistance of linear FET 56 Accordingly at the time FET transistor 52 is turned on to discharge capacitor 53 the output voltage from operational amplifier 55 is proportional to the flow rate Typically FET transistor 52 is reset at each flow reversal of fluid into cylinder 12 Thus the output volt age from operational amplifier 55 at this time represents the flow rate and can be sampled and suitably operated on by the other components of this invention in the manner described above APPENDIX A MICROL CCMPILZR VERSION 1 5 1 454 4 4 0459 2 MODULE 1 4 3 Edit H 44 4 5 T Created TIM 8 Date Last Edited WED 20 1980 6 01 PM 9 Last Edited By TIM 10 Date Last Compiled Assembled HED 20 1980 6 08 11 Last Compiled Assembled TIM 12 15 14 CONSTANT 15 TRUEZ1 FALSE O ADCMAX 35000 MINMIN z1200 HIGH REVERSAL POINT 4 C MINIMUM LOW REVERSAL POINT 18 2500 gt LOW REVERSAL POINT4 19 MINCON 53 C AUTORANGING SCALE CONSTANT 20 1 0 C STARTING VAL OF d VALVED GCFLOW 21 4 03 VALUE OF 22 MMIN 0 11 MIN VALUE OF dGCVALVE GCFLOW 23 UP 1 COWN 95 24 SLOPz251 FIXUP CONST FOR PLAY IN VALVE COUPLING 25 SCALE 123 043 CONVERSION CONST TO GET FLOW 26 MAXTIM 60003 SAMPLE TIME IN
58. essure changes can also be done in a similar 45 manner 0 20 25 30 16 FIG 56 illustrates a circuit which produces an output signal inversely proportional to time and therefore pro vides an output signal directly proportional to the flow rate In this circuit a reference voltage is applied to the negative input lead of operational amplifier 54 through input resistor 51 The positive input lead of operational amplifier 54 is connected through resistor 57 to ground The reference signal is integrated by capacitor 53 in a well known manner when the gate voltage on reset FET transistor 52 is such that this transistor is turned off i e non conducting The negative going output signal from operational amplifier 54 across capacitor 53 is then applied to the gate of depletion mode N channel FET transistor 56 This transistor is a linear FET device with the source drain resistance linearly proportional to the gate voltage Thus as the gate voltage decreases linearly with time the source drain resistance of this transistor a depletion mode device is normally conducting in creases with gate voltage Thus the output voltage from operational amplifier 55 the negative input lead of which is connected to a reference voltage through input resistor Rg and the positive input lead of which is con nected to a suitable reference drops hyperbolically with time since its output voltage is proportional to 1 Rr where Reis the source to drain r
59. f T Created TIM Date Last Edited THU 7 1980 5 39 9 Last Edited 10 Date Last Comnpiled Assembled THU 7 1980 516 11 Last Compiled Assembled Byz 12 13 4 5 14 3C Me Ce 0 15 M TJRAI ERU 1 15 3 MODULE 1 5 17 Fdit 50 2 9 18 7 19 5 20 21 Created TIM 22 3 Date Last Edited THU FEB 7 1980 5 49 23 Last Edited Hy TIM 44 45 47 4R 90 51 55 a4 SA 57 59 52 65 fi 68 69 71 74 TT 81 85 84 87 89 90 92 95 95 98 99 101 102 109 105 107 108 110 111 113 114 115 116 117 113 119 120 121 122 123 12 125 4 315 523 27 Date Lost Compiled Assemblod T 5 Last Compiled Assemoted SEXTFPRNAL M MISTRTI 1 MISTRT PROCEDURF SEINT 3 1 1 0009 DAT M RESEI 1 RESETIASSFMALY HINT M SETTN SETIN ASSEMBLY PROCEDURE RINT ADCINIASSFMBLY PROCEDUPEZINTEGE M ADCSTS 00 ADCSTSIASSFMALY PROCS DURE M ADCGU ADCGO ASSEMBLY PROCTDURFIRINTS M LFDOUJT 13 LFODOUTIASSCMHLY PROCEDURE ZHINT M 5INSIS 71 STNSTSIASS MALY M30UT5T SSEMPLY PROCFOJRC TM VILE M RIOIN 22 SIDINIASSLMSLY PROCEDURE ICH M SIOQUT SIOOUT ASSEMHLY PROCEDURE 4 M VLVON 1 VLVON ASSEH
60. f the answer is no the system moves directly to the logical hlocker stepper motor If the valve was adjusted in response to a set point change after the valve adjustment is completed the system also moves to the stepper motor logic The stepper motor logic determines whether or not the step per motor has moved to its desired position If the an swer is no then the system goes back to the initial sampling logic block If the answer to stepper motor done is yes the system begins a new sample and returns to sampling If the output of the system sampling block is yes the system determines whether the output of the sam pling compared to a reference sample is greater than DELMIN If the answer is yes the system deter mines whether or not the time is greater than the mini mum time If the answer is yes then the system com putes a new flow rate and depending upon the time adjusts the auto range of the system This last adjust ment is an adjustment to the reversal point of dia phragm 4 by changing the level of the output signal from sensor 6b at which the direction of motion of diaphragm 4 is reversed Once auto range has been completed a new valve position is calculated from the flow rate measurement compared to the set point and valve 79d is appropriately adjusted Finally an end of sample signal is produced which then causes the pro gram to initiate sampling again If on the other hand the output signal from the DE
61. g fluid whose flow is being mea sured through said first opening into said first chamber while withdrawing the fluid whose flow is being measured through said second opening from said second chamber and into response to a control signal reversing the chambers in which the fluid is inserted and from which the fluid is with drawn the movement of fluid into one chamber and out of the other chamber causing said flexible diaphragm to move into the chamber from which the fluid is being withdrawn means for continuously producing an output signal representative of the position of said magnet means for converting said output signal to a sequence of digital signals means for processing said sequence of digital signals to produce a second signal representative of the flow rate of said fluid into and out of said chamber means for comparing said flow rate to a reference flow rate to produce a control signal representative of the difference between said measured flow rate and said reference flow rate and means responsive to said control signal for changing the flow rate of said fluid 2 Structure comprising a chamber containing a first and second opening through which fluid can pass a flexible diaphragm located in said chamber so as to divide said chamber into two subchambers a first subchamber which is accessed through said first opening and a second subchamber which is ac cessed through said second opening a magnet attached to
62. l signal representative of the dif ference between said measured flow rate and said reference flow rate and changing the flow rate of said fluid in response to said control signal 11 Structure as in claim 2 wherein said means for producing comprises means for continuously producing an output signal representative of the instantaneous position of said magnet thereby to enable a measure of the instantaneous flow rate of the fluid entering said chamber to be obtained during the trave of said dia phragm from any one position to any other position in said chamber
63. mprises part of the flow meter in a flow control sys tem One or more sensing devices are mounted on the walls of the chamber to sense the instantaneous position of the diaphragm A novel electronic control circuit processes the data from the one or more sensing devices to provide measures of the flow rate during the dis 0 5 20 25 30 35 40 55 60 65 2 placement of the diaphragm along cylinder Signals are generated by the electronic control circuitry for switching a pair of three way valves one valve prising the input valve and the other valve comprising the output valve such that during one half of a cycle the input valve transfers fluid into the cylinder on one side of the diaphragm and during the other half of the cycle transfers fluid into the cylinder on the other side of the diaphragm The output valve is switched syn chronously with the input valve to transmit fluid from the other side or one side of the diaphragm to the output valve The electronic control system includes means for amplifying the output signals from the one or more sensing devices sensors to provide one or more signals representing the position of the diaphragm as a function of time means for converting the output sig nals from these amplifiers to digital form and computa tion means for operating on the digitized output signals from the sensing devices to provide control signals for controlling a second input valv
64. n This invention relates to an electronic flow control system using an electronically controlled positive dis placement flow meter 2 Prior Art Positive displacement flow meters are well known Thus British Pat No 1 051 710 published Dec 21 1966 discloses a positive displacement flow meter utilizing a cylinder wherein a reciprocating piston is controlled to move from one end to the other of the cylinder in re sponse to the alternate passage of the fluid whose flow is being measured into the cylinder at one or the other end of the piston As fluid under pressure enters one end of the cylinder via an inlet pipe the piston is pushed along the cylinder and the fluid which entered the cyl inder at the other end of the piston as a result of the previous stroke is forced into the outlet pipe Valves in a well known arrangement allow fluid to alternately enter one end of the cylinder and be withdrawn from the other end of the cylinder and vice versa Other positive displacement flow meters are shown in U S Pat No 2 772 664 issued Dec 4 1956 to Jones et al U S Pat No 3 181 360 issued May 4 1965 to Heder horst and U S Pat No 3 657 925 issued Apr 25 1972 to Gross The 710 664 925 and 360 patents all dis close reciprocating pistons as the positive displacement member However the 360 patent discloses in addition the use of a flexible diaphragm 18 to seal a rigid piston 16 FIG 1 of the 360 patent which travels be
65. n or vice versa means for continuously producing an output signal representative of the position of said diaphragm means for selectively controlling the flow into said first portion and out of said second portion and for reversing the flow as desired so that the fluid flows into the second portion and from the first portion means for processing the output signal from said means for producing including switching path means for selectively accessing the output signal from said means for producing conversion means for converting said output signal from said means for producing to a first digital signal buffer means for storing said first digital signal from said conversion means means for inputting to said system a second digital signal representing a desired fluid flow rate means for storing said second digital signal represent 4 315 523 55 ing said desired fluid flow rate processing means for operating on said first and sec ond digital signals to produce an estimate of the flow rate of fluid into and out of said chamber means for storing a signal representative of the flow rate calculated by said processing means and driver circuit means periodically actuated by said output signal from said processing means to move a control valve either open or closed in response to the output signal stored in said means for storing 9 Structure as in claim 8 including means for storing the output signal from said process ing means
66. on f c t is approximated by several straight line segments where f equals 5 flow rate c equals the count and t equals the time inter val which has elapsed The method achieves moderate accuracy over a lim ited range with good repeatability and produces a direct digital output for very low cost when implemented using discrete logic A further improvement is to continuously vary the rate of down counting by using for example a capaci tive discharge to drive a VCO whose oscillations are then used to drive the down count It may be necessary to use a capacitive charge if the VCO has a negative voltage to frequency characteristic In this case a base line 1 zero bias count would also be taken and sub tracted to produce the direct digital representation of the flow The capacitive discharge itself can produce an ap proximation of the flow as a voltage Accuracy and range is limited but can also be improved by multiple interval method described above with respect to the countdown technique The above embodiments disclose the use of sensing devices on the external walls of the chamber Under some circumstances the Hall effect sensor can be molded into the diaphragm with lead wires also in the diaphragm and the magnets can be placed on the exter nal walls of the cylinder Compensation for temperature can be done in either the transducer or externally by a computer using a temperature input Likewise compen sation for pr
67. output signal proportional to the position of the diaphragm Typically the bellows comprises either a metal or polymer material and the diaphragm likewise comprises a polymer or metal material FIG 26 shows a different construction wherein the diaphragm is attached between two portions of the cylinder Again a magnet 5 is mounted on the dia phragm 4 and coated with the diaphragm material thereby to protect it from the fluid whose flow is being measured The entry of fluid to the left chamber 126 displaces diaphragm 4 and magnet 5 to the right as with the structure of FIG 2a and similarly the entry of fluid to the right chamber displaces the diaphragm 4 and magnet 5 to the left again as with the structure of FIG Za The diaphragm is constructed such that its motion to the right or left occurs with very little friction or resis tive force Thus the flow of the fluid is not disturbed by the presence of the diaphragm In addition the weight of the diaphragm is kept very low thereby minimizing the inertia of the diaphragm Magnetic sensors 66 and are mounted on the left and right walls of the cylinder to detect the movement of the diaphragm mounted magnet 5 to or from a given wall In both FIGS 2a and 0 20 25 30 40 45 50 55 60 6 25 a conventional set of two three way flow valves such as shown in FIG 1 is used to first route the fluid into one chamber and out of the other chamber and then to reve
68. ove one setting in the proper direction to open Should the stepper motor be instructed to close rather than open then a hexadecimal encoded 5 would be transmitted in binary form on leads DO through D3 In this latter case wherein the most significant digit corresponds to a zero the second most significant digit corresponds to a one the third most significant digit corresponds to a zero and the fourth most significant digit corresponds to a one corresponding to the signals 0101 on leads D3 through DO respectively then the 1 on lead DO will drive the output signal from in verter 101 to a low level thereby turning on transistor and energizing winding W1 Diode D1 prevents voltage pulses generated by changing the current through winding W1 from burning out transistor Q1 and resistors 102 and 103 comprise pull up and base drive resistors respectively FIG 9 shows the circuitry associated with the Hall effect sensor 66 magnetic flux from the magnet 5 mounted within and as an integral part of diaphragm 4 is converted to a voltage and amplified to produce an output signal Hall effect sensor 66 preferably com prises part number 633SS2 made by Microswitch Inc a division of Honeywell The output signal from micro switch 90 is transmitted via twisted pair cable 94 to Analog Devices data acquisition board 84 FIGS 7 and 8 There this output signal activates the processor to operate in a way previously described Pull d
69. own resis tor 92 100 ohms is connected between the fifteen volt power supply in series with a 5 1 volt zener diode 91 to ground Variable resistor 93 100K is connected across the node between resistor 92 and diode 91 and ground Resistor 93 is used to produce a bias offset for the other lead in the twisted pair 94 transmitting the output pulse from microswitch 90 to the data acquisition board 84 This bias offset comprises a way of compensating for the fact that the curve of flux versus voltage for the Hall effect sensor does not pass through the origin By adjusting the setting of variable resistor 93 the input signal to the control circuitry is offset i e zero ad justed to provide a signal within a desired range of magnitude Operation of the above described structure is imple mented by a software program The Microl high level language version of this program is attached to this application as Appendix A This program uses the Mi crol Language which is described in the User s Manual Microl Language dated 8 1979 This Manual is incorporated herein by reference FIG 12 illustrates the logic flow diagram of the com puter program devised to operate microcomputer and timer 81 FIGS 7 and 8 in accordance with this inven tion The computer program is designed to operate on the output signals from sensors 65 as processed by the data acquisition board 84 to determine flow rates To do this one of several algorithms is emplo
70. plest form the flow into one side of the cylin der 12 is reversed when the diaphragm reaches its ex treme position one way or the other The flow rate can in this embodiment be simply measured by the time it takes for the diaphragm to travel between the two ex tremes That is the flow rate is equal to the volume between the two extreme positions of the diaphragm 4 divided by the time taken by the diaphragm to travel between these two positions FIGS 4 and 5a show an embodiment of this inven tion using a reed switch to detect the maximum dis placement of the diaphragm adjacent each of the two walls of the cylinder 12 The reed switch signal is trans mitted to a microcomputer control 30 which then calcu lates from the time taken for the two reed switches 46a and 466 to be sequentially actuated the measured flow rate This measured flow rate is compared to a reference flow rate set into memory and the difference is used to set a control valve 33 to bring about the proper flow rate Solenoids and solid state relays are also actuated by the microcomputer control 30 to reverse the fluid flow into cylinder 12 at the maximum displacement points of the diaphragm 4 FIG 5a shows a circuit schematic of the structure used to respond to the change in state of the reed switches 46a and 466 due to the approach of magnet 5 A flip flop comprising two 7400 NAND gates 41 and 42 has as one input signal to each of the NAND gates the output signal repre
71. representing the calculated flow rate and means for displaying the calculated fluid flow rate 10 The method of measuring a fluid flow rate using a chamber containing a first opening and a second open ing through which fluid can pass with a flexible dia phragm located in said chamber so as to divide said chamber into two subchambers a first subchamber which is accessed through said first opening and a sec ond subchamber which is accessed through said second opening and a magnet attached to said flexible dia phragm comprising directing the fluid whose flow is being measured through said first opening into said first subcham ber while withdrawing the fluid whose flow is being measured through said second opening from said second subchamber and in response to a con 25 35 45 56 trol signal reversing the subchambers in which the fluid is inserted and from which the fluid is with drawn the movement of fluid into one subchamber and out of the other subchamber causing said flexi ble diaphragm to move into the subchamber from which the fluid is being withdrawn producing a continuous output signal representative of the position of said magnet converting said output signal to a sequence of digital signals processing said sequence of digital signals to produce a second signal representative of the flow rate of said fluid into and out of said chamber comparing said flow rate to a reference flow rate to produce a contro
72. rresponding to two high level input signals to high level thereby driving the output signal from NAND gate 41 to low level This low level output signal is also amplified and used to turn on transistor Q10 thereby again activating a relay to reverse the two three way flow valves 1 and 2 FIG 1 and thereby again to re verse the fluid flow FIG 6 shows a typical curve of output signal from a Hall effect device such as sensor 65 or 6a in FIG 25 versus position of the flow diaphragm 4 This curve is substantially linear over short portions but gradually flattens out as the diaphragm 4 moves away from the Hall sensor The slope of voltage versus position i e displacement is negative such that the output voltage as a function of the distance of the diaphragm from the sensor increases with decreasing distance of the dia phragm from the sensor Operation of the sensor in a region of substantially steep slope gives greater sensitiv ity and accuracy to the measurement of the fluid flow than does operation in a region of flatter slope As will be discussed shortly this feature is used to enhance the accuracy of certain flow measurements FIG 7 discloses the preferred embodiment of this invention using a microcomputer controlled digital circuit to provide proper feedback signals to control the flow rate The microcomputer 81 operates on an output signal produced from the Hall effect sensor 65 mounted on the wall of the chamber 12 containing th
73. rse this pattern Contrary to the prior art meters using a free flowing piston wherein the fluid whose flow is being measured can often leak from the left chamber to the right cham ber and vice versa this invention uses a flexible low inertia diaphragm to seal one chamber from the other and thereby to prevent leakage while at the same time providing a relatively instantaneous measure of fluid flow rate FIG 3 shows the structure of FIG 1 or the cham bers of FIGS 2a and 25 in combination with an elec tronic controller 30 DC stepping motor 31 and a clutch or coupling 32 joining the stepping motor to a valve 33 typically a needle flow valve for controlling the flow of fluid The DC stepping motor 31 adjusts the position of the valve 33 until the flow rate detected by the meter corresponds to a flow rate setpoint input to the electronic controller 30 As will be shown later the electronic controller 30 preferably comprises a micro processor controlled digital circuit with an analog to digital converter a sampling circuit buffer stores mem ory and selected input and display elements The elec tronic controller 30 also controls the setting of the two three way valves 1 and 2 to ensure that the fluid flow into the meter and from the meter is reversed at appro priate times to obtain maximum accuracy in the flow measurements The system provides accurate and re sponsive feedback or feed forward if desired control In the sim
74. senting the state of a given reed switch Thus normally when reed switch 46a is open the signal level on input lead 41a to NAND gate 41 is at a high level corresponding to the 5 volt DC supply voltage The other input lead 415 is coupled to the output lead 41d from the other NAND gate 42 The output signal on lead 414 is normally high level for at least one low level input signal Thus with the signal on output lead 41c low level the signal on input lead 426 is 4 315 523 7 low level and the signal on output lead 414 from gate 42 is high level thereby holding the output signal from gate 41at low level When reed switch 46a is closed the input signal on lead 41a to NAND gate 41 goes low thereby driving the output signal from NAND gate 41 to a high level This high level output signal is transmit ted to input lead 426 of NAND gate 42 and drives the output signal from NAND gate 42 to a low level thereby latching up the output of NAND gate 41 to a high level The high level output signal from NAND gate 41 is amplified by amplifier 43 and turns off transis tor Q10 2N2904 thereby changing the current through a coil to close two relay control switches thereby acti vating solenoids to change the settings of the two three way valves 1 and 2 shown in FIG 1 and thus to reverse the flow When diaphragm 4 arrives at the other side of the cylinder 12 reed switch 465 closes thereby driving the output signal from NAND gate 42 from low level co
75. signals produced by sensor 66 The reference signal used to determine the magnitude and direction of change in the position of valve 794 is derived by comparing the signal representing the flow 4 315 523 9 rate computed from the signals from sensor 65 with another signal placed in input buffer 76c and derived from the setting of thumbwheel 77 The setting of thumbwheel 77 can be varied as desired by the operator thereby changing as desired the setting of control valve 79d Basically thumbwheel 77 converts a setting visible to the user to four binary coded decimal digits corre sponding to 16 bits These signals are held in input buffer 76c and are used by microcomputer 81 to calcu late the proper control signal to be transmitted through output latch 766 to control the setting of valve 79d Output latch 764 is configured to retain the output signals from microcomputer 81 corresponding to the latest reading of the flow rate The signals retained in latch 76d activate display 78 to display the latest value of flow rate calculated by microcomputer 81 Structures corresponding to those shown in FIG 7 are shown in FIG 8 Those elements shown in block diagram form in FIG 8 function as described above in connection with FIG 7 and thus will not be described in more detail here FIGS 11a and 11 show in more detail the thumb wheel circuitry 110a through 1105 and the display cir cuitry 114a through 1146 used with this invention The th
76. taining a different number of bits a differ ent level of accuracy can be obtained The output signal from A to D converter 75 is then transmitted to input buffer 76e Input buffer 76e buffers the output signal from A to D converter 75 and holds this information until a request for this information is received from microcomputer 81 Microcomputer 81 comprises a Mostek MK79612 CPU and Timer Board which contains a CPU corresponding to the well known Z80 microprocessor The MK79612 is shown in more detail in the Mostek publication entitled Series Microcomputer Modules Operations Manual for MDX CPU 1 and subtitled 280 Central Processor Module MDX CPU 1 copyright 1978 by Mostek Cor poration This document is also incorporated herein by reference FIG 8 shows the relationship of the Mostek MK79612 to the remainder of the circuit the compo nents of which are also shown in more detail in FIG 7 The control logic 76a input buffer 76e A to D con verter 75 and analog switch 74 comprise the Analog Devices RTI 1220 data acquisition board 84 shown as such in FIG 8 The output latches 766 76c and 764 comprise the Pro Log 7601 TTL I O board 83 also shown in FIG 8 The program memory of the microcomputer 81 com prises the Mostek MK79604 Eprom UART board 82 shown as such in FIG 8 The data bus interconnecting the CPU timer and the Eprom UART portions of the structure to the Pro Log 7601 TTL I O board and the Analog Devices RTI
77. tween two chambers in a cylinder to the cylinder wall As one chamber is filled with gas or fluid a like amount of gas or fluid is expelled from the other chamber Reversal of the chambers in which gas is inserted and from which the gas is removed causes the diaphragm to reciprocate back and forth across the chamber The number of strokes of the piston diaphragm combination with the diaphragm made of Teflon or rubber is representative of the volume of gas passing through the meter U S Pat No 3 974 825 issued Aug 17 1976 discloses a pump using a flexible pneumatically driven dia phragm for pumping blood in an artificial heart Each of the above structures has certain disadvan tages A piston introduces inertia and friction into the flow system thereby affecting the flow to be measured Moreover the fluid whose flow is being measured often leaks past the piston In addition the frequency re sponse of the system is limited by the inertia of the piston For accurate flow control a low inertia low friction accurate flow meter is required as an essential part of the control system SUMMARY OF THE INVENTION This invention overcomes certain of the disadvan tages of the prior art positive displacement flow meters In accordance with this invention a novel low friction low inertia flexible diaphragm containing a magnet formed as an integral part of the diaphragm is mounted chamber preferrably cylindrical The chamber co
78. uit of FIG 5 for producing an output voltage proportional to flow rate FIG 6 shows a typical output voltage versus dis placement curve used with this invention for calibrating the output voltage from a sensing element on the end of the cylinder to the position of the diaphragm within the cylinder FIG 7 shows the microcomputer based flow controi ler structure connected to the sensing element on the end of the chamber containing the diaphragm FIG 8 shows the relationship of the various circuit boards used to process the signals from the sensor and to control the settings of the three way flow valves 1 and 2 FIGS 1 and 7 which allow the fluid to pass into 4 315 523 3 or the other of the chambers in cylinder and which control the setting of the fluid control valve FIG 9 shows a sensor circuit useful with this inven tion FIG 10 shows the motor and solenoid driver circuits used with this invention FIGS and 116 show schematically the thumb wheel digit input circuit and the display circuits used with this invention FIG 12 shows the logic diagram for the computer program used in the microcomputer shown in FIG 7 as part of the structure of this invention and FIG 13 shows schematically the method and struc ture for fabricating the diaphragm with an enclosed magnet used with this invention DETAILED DESCRIPTION While this invention will be described in conjunction with specific components in
79. umbwheel is capable of inputting four digits into the circuit Each digit circuit 1106 110 and 110d comprises a replica of the specific circuit 1100 shown figuratively for digit one This circuit is of a type well known in the arts and thus will not be described in detail except to say that if the thumbwheel is set for example on a 7 the switches within the thumbwheel corresponding to the 4 2 and 1 level signals connected to the 5 supply voltage through resistors 1126 112 and 112d respec tively are closed thereby to provide an output signal for the TTL input at a level corresponding to the com plement of 7 negative logic Any other decimal digit from 0 to 9 is selected by closing the corresponding switches to provide an output signal of the proper level The display likewise comprises a four digit display Each display 114 1146 114 and 114d comprises a well known decoder driver for taking a BCD input and converting it to a digital number ranging from 0 to 9 Typically each display comprises an HP 7304 display of a type well known in the art FIG 10 shows in more detail a typical drive circuit of the type used to drive the stepper motor 79c and the solenoid driven three way valves 1 and 2 the latter two valves being used as described above to reverse the flow in chamber 12 The driver circuits are driven by signals on input leads 40 through 45 derived from the TTL I O card FIGS 7 and 8 The particular stepper motor
80. yed In the pre ferred mode of operation the flow rate is measured on a relatively continuous basis as a function of the displace ment of diaphragm 4 across chamber 12 with time This 4 315 523 1 preferred mode does not depend upon reversal of the direction of motion of diaphragm 4 to measure the flow rate but does set an optimum reversal point for changing the direction of motion of diaphragm 4 to ensure that at least a minimum voltage difference from sensor 65 as a function of the location of diaphragm 4 is obtained in a given time In the limit the minimum voltage difference per sample can be expanded to a value corresponding to the reversal point of the dia phragm In this situation the preferred mode reduces to the second reversal dependent mode In essence the software emulates the operation of the reed switch mode but in addition provides an autoranging capabil ity to be described later second mode of operation contemplated for use with this invention is a reversal dependent mode The program parameters are set to cover the highest and lowest expected flow rates which correspond to the shortest and longest times for diaphragm 10 to complete one cycle The setting of the reversal position for re versing the direction of motion of diaphragm 4 closer to its central neutral position results in a decrease in the cycle time In this mode of operation the reversal point is set to ensure at least one sample within

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