Fundamental Technologies

Voyager LECP Pages

APPENDIX A
Decommutation Map Record Format

The purpose of the Decommutation Map record is to supply the appropriate information to allow interpretation of engineering parameters from the spacecraft engineering telemetry. The record is composed of the Standard Record Header described in Appendix C, seven words of spares defined as the subheader and data block which contain the channel Identifier by commutator position (Table A-1). The channel Identifiers would contain the Measurement Number, Table 4 in document 618-205, FR-3-280A.

The commutator position states the timing reference and deck location and MF, as depicted in Figure A-5 below.

Figure A-1 diagrams the logical record structure.

Figure A-1. EDR Engineering Decommutation Map Record

HEADER
(60-32 bit words)		 SUBHEADER
7-32 bit words
(Spares)		 DECOMMUTATION MAP DATA BLOCK
(112-32 bit words)		 = (179 words)

Figure A-5 Engineering Telemetry Format Structure

The procedure for using the decom maps is as follows:

Figure A-4. EDR Engineering Decommutation Map Data Format

EDR
Data Word

Bits
31                 16

0

31                 16

0
1 MAP WORD 1
DECK 100		 MAP WORD 2
DECK 101		 MAP WORD 3
DECK 102		 MAP WORD 4
DECK 103
3 MAP WORD 5
DECK 104		 MAP WORD 6
DECK 105		 MAP WORD 7
DECK 106		 MAP WORD 8
DECK 107
5 MAP WORD 9
DECK 108		 MAP WORD 10
DECK 109		 MAP WORD 11
DECK 110		 MAP WORD 12
DECK 111
7 MAP WORD 13
DECK 112		 MAP WORD 14
DECK 113		 MAP WORD 15
DECK 114		 MAP WORD 16
DECK 115
9 MAP WORD 17
DECK 300		 MAP WORD 18
DECK 301		 MAP WORD 19
DECK 302		 MAP WORD 20
DECK 303
:

. . . .

23 MAP WORD 45
DECK 328		 MAP WORD 46
DECK 329		 MAP WORD 47
DECK 117		 MAP WORD 48
DECK 118
25 MAP WORD 49
DECK 119		 MAP WORD 50
DECK A00		 MAP WORD 51
DECK A01		 MAP WORD 52
DECK A02
:

. . . .
107 MAP WORD 213
DECK 213		 MAP WORD 214
DECK 214		 MAP WORD 215
DECK 215		 MAP WORD 216
DECK 216
109 MAP WORD 217
DECK 217		 MAP WORD 218
DECK 218		 MAP WORD 219
DECK 219		 MAP WORD 220
DECK 156
111 MAP WORD 221
DECK 157		 MAP WORD 222
DECK 158		 MAP WORD 223
DECK 159		 Spares

Next: Appendix B

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Last modified 4/25/05, Tizby Hunt-Ward
tizby@ftecs.com
Original page by I. Robertson