Revision 66d8e606a8d996ded60bc81d5edf319142a5fad9 authored by Ron Burkey on 04 October 2021, 11:49:55 UTC, committed by Ron Burkey on 04 October 2021, 11:49:55 UTC
SPS_BACK-UP_RCS_CONTROL.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: SPS_BACK-UP_RCS_CONTROL.agc
## Purpose: A section of Luminary revision 96.
## It is part of the reconstructed source code for the
## original release of the flight software for the Lunar
## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
## The code has been recreated from a previously reconstructed
## copy of Luminary 97 by undoing changes described in anomaly
## report LNY-59. The code has been adapted such that the
## resulting bugger words exactly match those specified for
## Luminary 96 in NASA drawing 2021152D, which gives relatively
## high confidence that the reconstruction is correct.
## Reference: pp. 1507-1510
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2019-08-04 MAS Created from Luminary 97.
## Page 1507
# PROGRAM NAME: SPSRCS
# AUTHOR: EDGAR M. OSHIKA (AC ELECTRONICS)
# MODIFIED: TO RETURN TO ALL AXES VIA Q BY P. S. WEISSMAN, OCT 7, 1968
# MODIFIED TO IMPROVE BENDING STABILITY BY G. KALAN, FEB. 14, 1969
#
# FUNCTIONAL DESCRIPTION:
# THIS PROGRAM CONTROLS THE FIRING OF ALL RCS JETS IN THE DOCKED CONFIGURATION ACCORDING TO THE FOLLOWING PHASE
# PLANE LOGIC.
#
# 1. JET SENSE TEST (SPSRCS)
# IF JETS ARE FIRING NEGATIVELY, SET OLDSENSE NEGATIVE AND CONTINUE
# IF JETS ARE FIRING POSITIVELY, SET OLDSENSE POSITIVE AND CONTINUE
# IF JETS ARE NOT FIRING, SET OLDSENSE TO ZERO AND GO TO OUTER RATE LIMIT TEST
#
# 2. RATE DEAD BAND TEST
# IF JETS ARE FIRING NEGATIVELY AND RATE IS GREATER THAN TARGET RATE, LEAVE
# JETS ON AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
# IF JETS ARE FIRING POSITIVELY AND RATE IS LESS THAN TARGET RATE, LEAVE
# JETS ON AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
#
# 3. OUTER RATE LIMIT TEST (SPSSTART)
# IF MAGNITUDE OF EDOT IS GREATER THAN 1.73 DEG/SEC SET JET FIRING TIME
# TO REDUCE RATE AND GO TO INHIBITION LOGIC. OTHERWISE, CONTINUE.
#
# 4. COAST ZONE TEST
# IF STATE (E,EDOT) IS BELOW LINE E + 4 X EDOT > -1.4 DEG AND EDOT IS LESS THAN 1.30 DEG/SEC SET JET TIME POSI-
# TIVE AND CONTINUE. OTHERWISE, SET JET FIRING TIME TO ZERO AND CONTINUE.
# IF STATE IS ABOVE LINE E + 4 X EDOT > +1.4 DEG AND EDOT IS GREATER THAN -1.30 DEG/SEC, SET JET TIME NEGATIVE
# AND CONTINUE. OTHERWISE, SET JET FIRING TIME TO ZERO AND CONTINUE.
#
# 5. INHIBITION LOGIC
# IF OLDSENSE IS NON-ZERO:
# A) RETURN IF JET TIME HAS SAME SIGN AS OLDSENSE
# B) SET INHIBITION COUNTER* AND RETURN IF JET TIME IS ZERO
# C) SET INHIBITION COUNTER,* SET JET TIME TO ZERO AND RETURN IF SIGN
# OF JET TIME IS OPPOSITE TO THAT OF OLDSENSE
# IF OLDSENSE IS ZERO:
# A) RETURN IF INHIBITION COUNTER IS NOT POSITIVE
# B) SET JET TIME TO ZERO AND RETURN IF INHIBITION COUNTER IS POSITIVE
# *NOTE: INHIBITION COUNTERS CAN BE SET TO 4 OR 10 FOR THE P, AND UV AXES,
# RESPECTIVELY, IN SPSRCS. THEY ARE DECREMENTED BY ONE AT THE BEGINNING OF
## Page 1508
# EACH DAP PASS.
#
# THE MINIMUM PULSE WIDTH OF THIS CONTROLLER IS DETERMINED BY THE REPETITION RATE AT WHICH THIS ROUTINE IS CALLED
# AND IS NOMINALLY 100 MS FOR ALL AXES IN DRIFTING FLIGHT. DURING POWERED FLIGHT THE MINIMUM IS 100 MS FOR THE
# P AXIS AND 200 MS FOR THE CONTROL OF THE U AND V AXES.
#
# CALLING SEQUENCE:
# INHINT
# TC IBNKCALL
# CADR SPSRCS
#
# EXIT:
# TC Q
#
# ALARM/ABORT MODE: NONE
#
# SUBROUTINES CALLED: NONE
#
# INPUT: E, EDOT
# TJP, TJV, TJU TJ MUST NOT BE NEGATIVE ZERO
#
# OUTPUT: TJP, TJV, TJU
BANK 21
SETLOC DAPS4
BANK
COUNT* $$/DAPBU
EBANK= TJU
RATELIM2 OCT 00632 # 1.125 DEG/SEC
POSTHRST CA HALF
NDX AXISCTR
TS TJU
CCS OLDSENSE
TCF POSCHECK # JETS FIRING POSITIVELY
TCF CTRCHECK # JETS OFF. CHECK INHIBITION CTR
NEGCHECK INDEX AXISCTR # JETS FIRING NEGATIVELY
CS TJU
CCS A
TC Q # RETURN
TCF +2
TCF +1 # JETS COMMANDED OFF. SET CTR AND RETURN
SETCTR INDEX AXISCTR # JET FIRING REVERSAL COMMANDED. SET CTR,
CA UTIME # SET JET TIME TO ZERO, AND RETURN
## Page 1509
INDEX AXISCTR
TS UJETCTR
ZAPTJ CA ZERO
INDEX AXISCTR
TS TJU
TC Q
POSCHECK INDEX AXISCTR
CA TJU
TCF NEGCHECK +2
CTRCHECK INDEX AXISCTR # CHECK JET INHIBITION COUNTER
CCS UJETCTR
TCF +2
TC Q # CTR IS NOT POSITIVE. RETURN
TCF ZAPTJ # CTR IS POSITIVE. INHIBIT FIRINGS
TC Q # CTR IS NOT POSITIVE. RETURN
OCT 00004
UTIME OCT 00012
OCT 00012
OLDSENSE EQUALS DAPTREG1
NEGFIRE CS ONE # JETS FIRING NEGATIVELY
TS OLDSENSE
CA EDOT
TCF +4
PLUSFIRE CA ONE
TS OLDSENSE
CS EDOT # RATE DEAD BAND TEST
LXCH A
CS DAPBOOLS # IF DRIFTBIT = 1, USE ZERO TARGET RATE
MASK DRIFTBIT # IF DRIFTBIT = 0, USE 0.10 RATE TARGET
CCS A
CA RATEDB1
AD L
EXTEND
BZMF SPSSTART
TCF POSTHRST +3
SPSRCS INDEX AXISCTR # JET SENSE TEST
CCS TJU
TCF PLUSFIRE # JETS FIRING POSITIVELY
TCF +2
TCF NEGFIRE # JETS FIRING NEGATIVELY
TS OLDSENSE # JETS OFF
SPSSTART CA EDOT # OUTER RATE LIMIT TEST
EXTEND
MP RATELIM1
CCS A
TCF NEGTHRST # OUTER RATE LIMIT EXCEEDED
TCF +2
TCF POSTHRST # OUTER RATE LIMIT EXCEEDED
CA EDOT # COAST ZONE TEST
## Page 1510
AD E
EXTEND
MP DKDB # PAD LOADED DEADBAND. FRESHSTART: 1.4 DEG
EXTEND
BZF TJZERO
EXTEND
BZMF +7
CA EDOT
AD RATELIM2
EXTEND
BZMF TJZERO
NEGTHRST CS HALF
TCF POSTHRST +1
+7 CS RATELIM2
AD EDOT
EXTEND
BZMF POSTHRST
TJZERO CA ZERO
TCF POSTHRST +1
RATELIM1 = CALLCODE # = 00032, CORRESPONDING TO 1.73 DEG/SEC
RATEDB1 = TBUILDFX # = 00045, CORRESPONDS TO 0.101 DEG/SEC
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