/soy/ - Soyjaks

# Website:www.ibiblio.org/apollo.
# Pages:793-797
# Mod history:2009-05-20 HGTranscribed 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 2021112-061
#16:27 JULY 14, 1969

# Page 793
BANK31
SETLOCFTHROT
BANK
EBANK=PIF
COUNT*$$/THROT

# * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
# HERE FC, DESIRED THRUST, AND FP, PRESENT THRUST, UNWEIGHTED, ARE COMPUTED.

THROTTLECAABDELV# COMPUTE PRESENT ACCELERATION IN UNITS OF
EXTEND# 2(-4) M/CS/CS, SAVING SERVICER TROUBLE
MP/AF/CNST
+3EXTEND
QXCHRTNHOLD
AFDUMPTCMASSMULT
DXCHFP# FP = PRESENT THRUST
EXTEND
DCA/AFC/
TCMASSMULT
TSFC# FC = THRUST DESIRED BY GUIDANCE
DXCHFCODD# 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.

CSTTHROT# THIS CODING ASSUMES A FLATOUT WITHIN
ADTIME1# 80 SECONDS BEFORE FIRST THROTTLE CALL
MASKPOSMAX
COM
AD3SECS
EXTEND
BZMFWHERETO# BRANCH IF (TIME1-TTHROT +1) > 3 SECONDS
EXTEND
DCAFWEIGHT
DASFP

# 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.

WHERETOCAEBANK5# INITIALIZE L*WCR*T AND H*GHCR*T FROM
TSEBANK# PAD LOADED ERASABLES IN W-MATRIX
# Page 794
EBANK=LOWCRIT
EXTEND
DCALOWCRIT
DXCHL*WCR*T
CAEBANK7
TSEBANK
EBANK=PIF
CSZERO# INITIALIZE PIFPSET
TSPIFPSET
CSH*GHCR*T
ADFCOLD
EXTEND
BZMFLOWFCOLD# BRANCH IF FCOLD < OR = HIGHCRIT
CSL*WCR*T
ADFCODD
EXTEND
BZMFFCOMPSET# BRANCH IF FC < OR = LOWCRIT
CAFP# SEE NOTE 1
TCFFLATOUT1

FCOMPSETCSFMAXODD# SEE NOTE 2
ADFP
TCFFLATOUT2

LOWFCOLDCSH*GHCR*T
ADFCODD
EXTEND
BZMFDOPIF# BRANCH IF FC < OR = HIGHCRIT

CAFMAXPOS# NO: THROTTLE-UP
FLATOUT1DXCHFCODD
CAFEXTRA
FLATOUT2TSPIFPSET

# NOTE 1FC IS SET EQUAL TO FP SO PIF WILL BE ZERO. THIS IS DESIRABLE
#AS THERE IS ACTUALLY NO THROTTLE CHANGE.
#
# NOTE 2HERE, 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.

DOPIFTCFASTCHNG
EXTEND
DCAFCODD
TSFCOLD
DXCHPIF
EXTEND
# Page 795
DCSFP
DASPIF# PIF = FC - FP, NEVER EQUALS +0

DOITCAPIF
ADPIFPSET# ADD IN PIFPSET, WITHOUT CHANGING PIF
TSPSEUDO55
TSTHRUST
CAFBIT4
EXTEND
WORCHAN14
CATIME1
TSTTHROT

# 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 PPROCESS 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.

CATHISTPIP +1# INITIALIZE FWEIGHT COMP AS IF FOR P66
TSBUF

CSMODREG# ARE WE IN FACT IN P66?
ADDEC66
EXTEND
BZFFWCOMP# YES

CAPIPTIME +1# NO: INITIALIZE FOR TWO SECOND PERIOD
TSBUF
CAF4SECS
TCFFWCOMP +1

* * *