GE Multilin
C60 Breaker Protection System
B-3
APPENDIX B
B.1 MODBUS RTU PROTOCOL
B
Table B–3: MODBUS RTU CRC-16 ALGORITHM
SYMBOLS:
-->
data transfer
A
16 bit working register
Alow
low order byte of A
Ahigh
high order byte of A
CRC
16 bit CRC-16 result
i,j
loop counters
(+)
logical EXCLUSIVE-OR operator
N
total number of data bytes
Di
i-th data byte (i = 0 to N-1)
G
16 bit characteristic polynomial = 1010000000000001 (binary) with MSbit dropped and bit order reversed
shr (x)
right shift operator (th LSbit of x is shifted into a carry flag, a '0' is shifted into the MSbit of x, all other bits
are shifted right one location)
ALGORITHM:
1.
FFFF (hex) --> A
2.
0 --> i
3.
0 --> j
4.
Di (+) Alow --> Alow
5.
j + 1 --> j
6.
shr (A)
7.
Is there a carry?
No: go to 8; Yes: G (+) A --> A and continue.
8.
Is j = 8?
No: go to 5; Yes: continue
9.
i + 1 --> i
10.
Is i = N?
No: go to 3; Yes: continue
11.
A --> CRC
Summary of Contents for C60
Page 10: ...x C60 Breaker Protection System GE Multilin TABLE OF CONTENTS ...
Page 30: ...1 20 C60 Breaker Protection System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Page 420: ...5 284 C60 Breaker Protection System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Page 466: ...8 4 C60 Breaker Protection System GE Multilin 8 1 FAULT LOCATOR 8 THEORY OF OPERATION 8 ...
Page 478: ...9 12 C60 Breaker Protection System GE Multilin 9 6 DISPOSAL 9 MAINTENANCE 9 ...
Page 492: ...A 14 C60 Breaker Protection System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Page 648: ...E 10 C60 Breaker Protection System GE Multilin E 1 OVERVIEW APPENDIX E E ...
Page 660: ...F 12 C60 Breaker Protection System GE Multilin F 2 DNP POINT LISTS APPENDIX F F ...
Page 670: ...H 8 C60 Breaker Protection System GE Multilin H 2 ABBREVIATIONS APPENDIX H H Z Impedance Zone ...
Page 672: ...H 10 C60 Breaker Protection System GE Multilin H 3 WARRANTY APPENDIX H H ...
Page 682: ...x C60 Breaker Protection System GE Multilin INDEX ...