225 lines
5.8 KiB
Plaintext
225 lines
5.8 KiB
Plaintext
# 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.
|
|
|
|
THROTTLE CA ABDELV # COMPUTE PRESENT ACCELERATION IN UNITS OF
|
|
EXTEND # 2(-4) M/CS/CS, SAVING SERVICER TROUBLE
|
|
MP /AF/CNST
|
|
+3 EXTEND
|
|
QXCH RTNHOLD
|
|
AFDUMP TC MASSMULT
|
|
DXCH FP # FP = PRESENT THRUST
|
|
EXTEND
|
|
DCA /AFC/
|
|
TC MASSMULT
|
|
TS FC # FC = THRUST DESIRED BY GUIDANCE
|
|
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.
|
|
|
|
CS TTHROT # THIS CODING ASSUMES A FLATOUT WITHIN
|
|
AD TIME1 # 80 SECONDS BEFORE FIRST THROTTLE CALL
|
|
MASK POSMAX
|
|
COM
|
|
AD 3SECS
|
|
EXTEND
|
|
BZMF WHERETO # BRANCH IF (TIME1-TTHROT +1) > 3 SECONDS
|
|
EXTEND
|
|
DCA FWEIGHT
|
|
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.
|
|
|
|
WHERETO CA EBANK5 # INITIALIZE L*WCR*T AND H*GHCR*T FROM
|
|
TS EBANK # PAD LOADED ERASABLES IN W-MATRIX
|
|
# Page 794
|
|
EBANK= LOWCRIT
|
|
EXTEND
|
|
DCA LOWCRIT
|
|
DXCH L*WCR*T
|
|
CA EBANK7
|
|
TS EBANK
|
|
EBANK= PIF
|
|
CS ZERO # INITIALIZE PIFPSET
|
|
TS PIFPSET
|
|
CS H*GHCR*T
|
|
AD FCOLD
|
|
EXTEND
|
|
BZMF LOWFCOLD # BRANCH IF FCOLD < OR = HIGHCRIT
|
|
CS L*WCR*T
|
|
AD FCODD
|
|
EXTEND
|
|
BZMF FCOMPSET # BRANCH IF FC < OR = LOWCRIT
|
|
CA FP # SEE NOTE 1
|
|
TCF FLATOUT1
|
|
|
|
FCOMPSET CS FMAXODD # SEE NOTE 2
|
|
AD FP
|
|
TCF FLATOUT2
|
|
|
|
LOWFCOLD CS H*GHCR*T
|
|
AD FCODD
|
|
EXTEND
|
|
BZMF DOPIF # BRANCH IF FC < OR = HIGHCRIT
|
|
|
|
CA FMAXPOS # NO: THROTTLE-UP
|
|
FLATOUT1 DXCH FCODD
|
|
CA FEXTRA
|
|
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.
|
|
|
|
DOPIF TC FASTCHNG
|
|
EXTEND
|
|
DCA FCODD
|
|
TS FCOLD
|
|
DXCH PIF
|
|
EXTEND
|
|
# Page 795
|
|
DCS FP
|
|
DAS PIF # PIF = FC - FP, NEVER EQUALS +0
|
|
|
|
DOIT CA PIF
|
|
AD PIFPSET # ADD IN PIFPSET, WITHOUT CHANGING PIF
|
|
TS PSEUDO55
|
|
TS THRUST
|
|
CAF BIT4
|
|
EXTEND
|
|
WOR CHAN14
|
|
CA TIME1
|
|
TS TTHROT
|
|
|
|
# SINCE /AF/ IS NOT AN INSTANTANEOUS ACCELERATION, 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.
|
|
|
|
CA THISTPIP +1 # INITIALIZE FWEIGHT COMP AS IF FOR P66
|
|
TS BUF
|
|
|
|
CS MODREG # ARE WE IN FACT IN P66?
|
|
AD DEC66
|
|
EXTEND
|
|
BZF FWCOMP # YES
|
|
|
|
CA PIPTIME +1 # NO: INITIALIZE FOR TWO SECOND PERIOD
|
|
TS BUF
|
|
CAF 4SECS
|
|
TCF FWCOMP +1
|
|
|
|
FWCOMP CAF 2SECS
|
|
+1 TS Q
|
|
EXTEND
|
|
MP BIT6
|
|
LXCH BUF +1
|
|
CS BUF # TIME OF LAST PIPA READING.
|
|
AD TIME1
|
|
AD THROTLAG # COMPENSATE FOR ENGINE RESPONSE LAG
|
|
MASK LOW8 # MAKE SURE SMALL AND POSITIVE
|
|
ZL
|
|
EXTEND
|
|
# Page 796
|
|
DV Q
|
|
EXTEND
|
|
MP PIF
|
|
DOUBLE
|
|
DXCH FWEIGHT
|
|
CCS PIF
|
|
AD ONE
|
|
TCF +2
|
|
AD ONE
|
|
EXTEND
|
|
MP PIF
|
|
EXTEND
|
|
DV BUF +1
|
|
ZL
|
|
DAS FWEIGHT
|
|
|
|
THDUMP TC RTNHOLD
|
|
|
|
# FLATOUT THROTTLES UP THE DESCENT ENGINE, AND IS CALLED AS A BASIC SUBROUTINE.
|
|
|
|
FLATOUT CAF BIT13 # 4096 PULSES
|
|
WHATOUT TS PIFPSET # USE PIFPSET SO FWEIGHT WILL BE ZERO
|
|
CS ZERO
|
|
TS FCOLD
|
|
TS PIF
|
|
EXTEND
|
|
QXCH RTNHOLD
|
|
TCF DOIT
|
|
|
|
# MASSMULT SCALES ACCELERATION, ARRIVING IN A AND L IN UNITS OF 2(-4) M/CS/CS, TO FORCE IN PULSE UNITS.
|
|
|
|
MASSMULT EXTEND
|
|
QXCH BUF
|
|
DXCH MPAC
|
|
TC DMP
|
|
ADRES MASS
|
|
TC DMP # LEAVES PROPERLY SCALED FORCE IN MPAC
|
|
ADRES SCALEFAC
|
|
TC TPAGREE
|
|
CA MPAC
|
|
EXTEND
|
|
BZF +3
|
|
CAF POSMAX
|
|
TC BUF
|
|
DXCH MPAC +1
|
|
TC BUF
|
|
# Page 797
|
|
# CONSTANTS --
|
|
|
|
FEXTRA = BIT13 # FEXT +5.13309020 E+4
|
|
|
|
/AF/CNST DEC .13107
|
|
|
|
# * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
|