Source Code

034184,000001: 034185,000002: 034186,000003: 034187,000004: 034188,000005: 034189,000006: 034190,000007: 034191,000008: 034192,000009: 034193,000010: 034194,000011: 034195,000012: 034196,000013: 034197,000014: 034198,000015: 034199,000016: 034200,000017: 034201,000018: 034202,000019: 034203,000020: 034204,000021: 034205,000022: 034206,000023: 034207,000024: 034208,000025: 034209,000026: 034210,000027: 034211,000028: 31,2216 034212,000029: 31,2000 034213,000030: 31,2000 034214,000031: 31,2216 E7,1612 034215,000032: 31,2216 034216,000033: 034217,000034: 034218,000035: 034219,000036: < 034298,000115: 31,2303 034299,000116: 31,2304 034300,000117: 31,2305 034301,000118: 31,2306 034302,000119: 31,2307 034303,000120: 034304,000121: 31,2310 034305,000122: 31,2311 034306,000123: # Copyright: Public domain. # Filename: THROTTLE_CONTROL_ROUTINES.agc # Purpose: Part of the source code for Luminary 1A build 099. # It is part of the source code for the Lunar Module's (LM) # Apollo Guidance Computer (AGC), for Apollo 11. # Assembler: yaYUL # Contact: HARTMUTH GUTSCHE <hgutsche@xplornet.com>. # Website: www.ibiblio.org/apollo. # Pages: 793-797 # Mod history: 2009-05-20 HG Transcribed from page images. # This source code has been transcribed or otherwise adapted from # digitized images of a hardcopy from the MIT Museum. The digitization # was performed by Paul Fjeld, and arranged for by Deborah Douglas of # the Museum. Many thanks to both. The images (with suitable reduction # in storage size and consequent reduction in image quality as well) are # available online at www.ibiblio.org/apollo. If for some reason you # find that the images are illegible, contact me at info@sandroid.org # about getting access to the (much) higher-quality images which Paul # actually created. # Notations on the hardcopy document read, in part: # Assemble revision 001 of AGC program LMY99 by NASA 2021112-61 # 16:27 JULY 14, 1969 # Page 793 BANK 31 SETLOC FTHROT BANK EBANK= PIF COUNT* $$/THROT # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * # HERE FC, DESIRED THRUST, AND FP, PRESENT THRUST, UNWEIGHTED, ARE COMPUTED. C45">034220,000037: 31,2216 31246 THROTTLE CA ABDELV # COMPUTE PRESENT ACCELERATION IN UNITS OF 00006 EXTEND # 2(-4) M/CS/CS, SAVING SERVICER TROUBLE 72417 MP /AF/CNST 00006 +3 EXTEND 23607 QXCH RTNHOLD >034225,000042: 31,2223 02400 AFDUMP TC MASSMULT 53470 DXCH FP # FP = PRESENT THRUST 00006 EXTEND 31464 DCA /AFC/ 02400 TC MASSMULT 55615 TS FC # FC = THRUST DESIRED BY GUIDANCE 53466 DXCH FCODD # FCODD = WHAT IT IS GOING TO GET # 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 62244 BZMF WHERETO # BRANCH IF (TIME1-TTHROT +1) > 3 SECONDS 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">034250,000067: 31,2244 35014 WHERETO CA EBANK5 # INITIALIZE L*WCR*T AND H*GHCR*T FROM 54003 TS EBANK # PAD LOADED ERASABLES IN W-MATRIX # Page 794 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 62272 BZMF LOWFCOLD # BRANCH IF FCOLD < OR = HIGHCRIT 40130 CS L*WCR*T 61465 AD FCODD 00006 EXTEND 62267 BZMF FCOMPSET # BRANCH IF FC < OR = LOWCRIT 31467 CA FP # SEE NOTE 1 12277 TCF FLATOUT1 554">034273,000090: 31,2267 42002 FCOMPSET CS FMAXODD # SEE NOTE 2 61467 AD FP 12301 TCF FLATOUT2 C44">034277,000094: 31,2272 40131 LOWFCOLD CS H*GHCR*T 61465 AD FCODD 00006 EXTEND 62302 BZMF DOPIF # BRANCH IF FC < OR = HIGHCRIT 32003 CA FMAXPOS # NO: THROTTLE-UP 431">034283,000100: 31,2277 53466 FLATOUT1 DXCH FCODD 34737 CA FEXTRA 432">034285,000102: 31,2301 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 # (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>034297,000114: 31,2302 03740 DOPIF TC FASTCHNG 00006 EXTEND 31466 DCA FCODD 55620 TS FCOLD 53613 DXCH PIF 00006 EXTEND # Page 795 41470 DCS FP 21613 DAS PIF # PIF = FC - FP, NEVER EQUALS +0 >034307,000124: 31,2312 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 41011 CS MODREG # ARE WE IN FACT IN P66? 62501 AD DEC66 00006 EXTEND 12335 BZF FWCOMP # YES 31235 CA PIPTIME +1 # NO: INITIALIZE FOR TWO SECOND PERIOD 54130 TS BUF 35003 CAF 4SECS 12336 TCF FWCOMP +1 >034342,000159: 31,2335 35000 FWCOMP CAF 2SECS 54002 +1 TS Q 00006 EXTEND 74746 MP BIT6 22131 LXCH BUF +1 40130 CS BUF # TIME OF LAST PIPA READING. 60025 AD TIME1 62004 AD THROTLAG # COMPENSATE FOR ENGINE RESPONSE LAG 74357 MASK LOW8 # MAKE SURE SMALL AND POSITIVE 22007 ZL 00006 EXTEND # Page 796 10002 DV Q 00006 EXTEND 71612 MP PIF 60000 DOUBLE 53611 DXCH FWEIGHT 11612 CCS PIF 64753 AD ONE 12361 TCF +2 64753 AD ONE 00006 EXTEND 71612 MP PIF 00006 EXTEND 10131 DV BUF +1 22007 ZL 21611 DAS FWEIGHT >034370,000187: 31,2367 01607 THDUMP TC RTNHOLD # FLATOUT THROTTLES UP THE DESCENT ENGINE, AND IS CALLED AS A BASIC SUBROUTINE. 4">034374,000191: 31,2370 34737 FLATOUT CAF BIT13 # 4096 PULSES 4">034375,000192: 31,2371 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 12312 TCF DOIT # MASSMULT SCALES ACCELERATION, ARRIVING IN A AND L IN UNITS OF 2(-4) M/CS/CS, TO FORCE IN PULSE UNITS. C54">034385,000202: 31,2400 00006 MASSMULT EXTEND 22130 QXCH BUF 52155 DXCH MPAC 07103 TC DMP 01244 ADRES MASS 07103 TC DMP # LEAVES PROPERLY SCALED FORCE IN MPAC 02005 ADRES SCALEFAC 07257 TC TPAGREE 30154 CA MPAC 00006 EXTEND 12415 BZF +3 34733 CAF POSMAX 00130 TC BUF 52156 DXCH MPAC +1 00130 TC BUF # Page 797 # CONSTANTS -- >034403,000220: 31,2417 4737 FEXTRA = BIT13 # FEXT +5.13309020 E+4 354">034405,000222: 31,2417 04143 /AF/CNST DEC .13107 # * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * THROTTLE_CONTROL_ROUTINES.agc. Parent file is MAIN.agc