Source Code

033092,000001: 033093,000002: 033094,000003: 033095,000004: 033096,000005: 033097,000006: 033098,000007: 033099,000008: 033100,000009: 033101,000010: 033102,000011: 033103,000012: 033104,000013: 033105,000014: 033106,000015: 033107,000016: 033108,000017: 31,2144 033109,000018: 31,2000 033110,000019: 31,2000 033111,000020: 31,2144 E7,1612 033112,000021: 31,2144 033113,000022: 033114,000023: 033115,000024: 033116,000025: < 033208,000117: 31,2242 033209,000118: 31,2243 033210,000119: 31,2244 033211,000120: 31,2245 033212,000121: 31,2246 033213,000122: 31,2247 033214,000123: 31,2250 033215,000124: # Copyright: Public domain. # Filename: THROTTLE_CONTROL_ROUTINES.agc # Purpose: A section of Luminary 1C, revision 131. # It is part of the source code for the Lunar Module's (LM) # Apollo Guidance Computer (AGC) for Apollo 13 and Apollo 14. # This file is intended to be a faithful transcription, except # that the code format has been changed to conform to the # requirements of the yaYUL assembler rather than the # original YUL assembler. # Reference: pp. 793-797 of 1729.pdf. # Contact: Ron Burkey <info@sandroid.org>. # Website: www.ibiblio.org/apollo/index.html # Mod history: 05/24/03 RSB. Began transcribing. # 05/14/05 RSB Corrected website reference above. # Page 793 BANK 31 SETLOC FTHROT BANK EBANK= PIF COUNT* $$/THROT # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * # HERE FC, DESIRED THRUST, AND FP, PRESENT THRUST, UNWEIGHTED, ARE COMPUTED. C45">033117,000026: 31,2144 31245 THROTTLE CA ABDELV # COMPUTE PRESENT ACCELERATION IN UNITS OF 00006 EXTEND # 2(-4) M/CS/CS, SAVING SERVICER TROUBLE 72356 MP /AF/CNST 00006 +3 EXTEND 23607 QXCH RTNHOLD >033122,000031: 31,2151 02337 AFDUMP TC MASSMULT 53470 DXCH FP # FP = PRESENT THRUST 00006 EXTEND 31464 DCA /AFC/ 02337 TC MASSMULT 55615 TS FC # FC = THRUST DESIRED BY GUIDANCE 53466 DXCH FCODD # FCODD = WHAT IT IS GOING TO GET # COMPUTE DESIRED THRUST FOR DISPLAY AS A PERCENTAGE OF 10,500 POUNDS 32360 CAF 4FMAXNOM # MOVE 4FMAXNOM TO ERASABLE FOR DV BELOW 54002 TS Q 31615 CA FC 72357 MASK OCT17777 # FOR SAFETY 00006 EXTEND 10002 DV Q 00006 EXTEND 75003 MP 4SECS 55750 TS THRDISP # FOR DISPLAY IN N92 # IF IT HAS BEEN LESS THAN 3 SECONDS SINCE THE LAST THROTTLING, AUGMENT FP USING THE FWEIGHT CALCULATED THEN. 41617 CS TTHROT # THIS CODING ASSUMES A FLATOUT WITHIN 60025 AD TIME1 # 80 SECONDS BEFORE FIRST THROTTLE CALL 74733 MASK POSMAX 40000 COM 65002 AD 3SECS 00006 EXTEND 62203 BZMF WHERETO # BRANCH IF (TIME1-TTHROT +1) > 3 SECONDS # Page 794 00006 EXTEND 31611 DCA FWEIGHT 21470 DAS FP # THIS LOGIC DETERMINES THE THROTTLING IN THE REGION 10% - 94%. THE MANUAL THROTTLE, NOMINALLY SET AT # MINIMUM BY ASTRONAUT OR MISSION CONTROL PROGRAMS, PROVIDES THE LOWER BOUND. A STOP IN THE THROTTLE HARDWARE # PROVIDES THE UPPER. F">033160,000069: 31,2203 35014 WHERETO CA EBANK5 # INITIALIZE L*WCR*T AND H*GHCR*T FROM 54003 TS EBANK # PAD LOADED ERASABLES IN W-MATRIX EBANK= LOWCRIT 00006 EXTEND 31507 DCA LOWCRIT 52131 DXCH L*WCR*T 35016 CA EBANK7 54003 TS EBANK EBANK= PIF 44755 CS ZERO # INITIALIZE PIFPSET 55606 TS PIFPSET 40131 CS H*GHCR*T 61620 AD FCOLD 00006 EXTEND 62231 BZMF LOWFCOLD # BRANCH IF FCOLD < OR = HIGHCRIT 40130 CS L*WCR*T 61465 AD FCODD 00006 EXTEND 62226 BZMF FCOMPSET # BRANCH IF FC < OR = LOWCRIT 31467 CA FP # SEE NOTE 1 12236 TCF FLATOUT1 554">033182,000091: 31,2226 42002 FCOMPSET CS FMAXODD # SEE NOTE 2 61467 AD FP 12240 TCF FLATOUT2 C44">033186,000095: 31,2231 40131 LOWFCOLD CS H*GHCR*T 61465 AD FCODD 00006 EXTEND 62241 BZMF DOPIF # BRANCH IF FC < OR = HIGHCRIT 32003 CA FMAXPOS # NO: THROTTLE-UP 431">033192,000101: 31,2236 53466 FLATOUT1 DXCH FCODD 34737 CA FEXTRA 432">033194,000103: 31,2240 55606 FLATOUT2 TS PIFPSET # NOTE 1 FC IS SET EQUAL TO FP SO PIF WILL BE ZERO. THIS IS DESIRABLE # AS THERE IS ACTUALLY NO THROTTLE CHANGE. # NOTE2 HERE, SINCE WE ARE ABOUT TO RETURN TO THE THROTTLEABLE REGION # Page 795 # (BELOW 55%) THE QUANTITY -(FMAXODD-FP) IS COMPUTED AND PUT # INTO PIFPSET TO COMPENSATE FOR THE DIFFERENCE BETWEEN THE # NUMBER OF BITS CORRESPONDING TO FULL THROTTLE (FMAXODD) AND THE # NUMBER CORRESPONDING TO ACTUAL THRUST (FP). THUS THE TOTAL # THROTTLE COMMAND PIF = FC - FP - (FMAXODD - FP) = FC - FMAXODD. /a>033207,000116: 31,2241 03677 DOPIF TC FASTCHNG 00006 EXTEND 31466 DCA FCODD 55620 TS FCOLD 53613 DXCH PIF 00006 EXTEND 41470 DCS FP 21613 DAS PIF # PIF = FC - FP, NEVER EQUALS +0 >033216,000125: 31,2251 31612 DOIT CA PIF 61606 AD PIFPSET # ADD IN PIFPSET, WITHOUT CHANGING PIF 55614 TS PSEUDO55 54055 TS THRUST 34750 CAF BIT4 00006 EXTEND 05014 WOR CHAN14 30025 CA TIME1 55617 TS TTHROT # SINCE /AF/ IS NOT AN INSTANTANEOUS ACELERATION, BUT RATHER AN "AVERAGE" OF THE ACCELERATION LEVELS DURING # THE PRECEEDING PIPA INTERVAL, AND SINCE FP IS COMPUTED DIRECTLY FROM /AF/, FP IN ORDER TO CORRESPOND TO THE # ACTUAL THRUST LEVEL AT THE END OF THE INTERVAL MUST BE WEIGHTED BY # PIF(PPROCESS + TL) PIF /PIF/ # FWEIGHT = ------------------ + ------------- # PGUID 2 PGUID FRATE # WHERE PROCESS IS THE TIME BETWEEN PIPA READING AND THE START OF THROTTLING, PGUID IS THE GUIDANCE PERIOD, AND # FRATE IS THE THROTTLING RATE (32 UNITS PER CENTISECOND). PGUID IS EITHER 1 OR 2 SECONDS. THE "TL" IN THE # FIRST TERM REPRESENTS THE ENGINE'S RESPONSE LAG. HERE FWEIGHT IS COMPUTED FOR USE NEXT PASS. 31762 CA THISTPIP +1 # INITIALIZE FWEIGHT COMP AS IF FOR P66 54130 TS BUF 41010 CS MODREG # ARE WE IN FACT IN P66? 62452 AD DEC66 00006 EXTEND 12274 BZF FWCOMP # YES 31234 CA PIPTIME +1 # NO: INITIALIZE FOR TWO SECOND PERIOD 54130 TS BUF 35003 CAF 4SECS 12275 TCF FWCOMP +1 # Page 796 >033250,000159: 31,2274 35000 FWCOMP CAF 2SECS 54002 +1 TS Q 00006 EXTEND 74746 MP BIT6 22131 LXCH BUF +1 40130 CS BUF # TIME OF LAST PIPA READIN. 60025 AD TIME1 62004 AD THROTLAG # COMPENSATE FOR ENGINE RESPONSE LAG 74357 MASK LOW8 # MAKE SURE SMALL AND POSITIVE 22007 ZL 00006 EXTEND 10002 DV Q 00006 EXTEND 71612 MP PIF 60000 DOUBLE 53611 DXCH FWEIGHT 11612 CCS PIF 64753 AD ONE 12320 TCF +2 64753 AD ONE 00006 EXTEND 71612 MP PIF 00006 EXTEND 10131 DV BUF +1 22007 ZL 21611 DAS FWEIGHT >033277,000186: 31,2326 01607 THDUMP TC RTNHOLD # FLATOUT THROTTLES UP THE DESCENT ENGINE, AND IS CALLED AS A BASIC SUBROUTINE. 4">033281,000190: 31,2327 34737 FLATOUT CAF BIT13 # 4096 PULSES 4">033282,000191: 31,2330 55606 WHATOUT TS PIFPSET # USE PIFPSET SO FWEIGHT WILL BE ZERO 44755 CS ZERO 55620 TS FCOLD 55612 TS PIF 00006 EXTEND 23607 QXCH RTNHOLD 12251 TCF DOIT # MASSMULT SCALES ACCELERATION, ARRIVING IN A AND L IN UNITS OF 2(-4) M/CS/CS, TO FORCE IN PULSE UNITS. C54">033292,000201: 31,2337 00006 MASSMULT EXTEND 22130 QXCH BUF 52155 DXCH MPAC 07106 TC DMP 01243 ADRES MASS # Page 797 07106 TC DMP # LEAVES PROPERLY SCALED FORCE IN MPAC 02005 ADRES SCALEFAC 07262 TC TPAGREE 30154 CA MPAC 00006 EXTEND 12354 BZF +3 34733 CAF POSMAX 00130 TC BUF 52156 DXCH MPAC +1 00130 TC BUF # CONSTANTS -- >033311,000220: 31,2356 4737 FEXTRA = BIT13 # FEXT +5.13309020 E+4 354">033313,000222: 31,2356 04143 /AF/CNST DEC .13107 737">033315,000224: 31,2357 17777 OCT17777 OCT 17777 F4D">033316,000225: 31,2360 35074 4FMAXNOM DEC 14908 B-14 # EQUIVALENT TO 10,500 LBS. # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * THROTTLE_CONTROL_ROUTINES.agc. Parent file is MAIN.agc