Mitsubishi Melsec-L Series User Manual page 382

CRC error checking procedure
(Load a 16-bit register whose bits are all '1')
02 (Station number)
H
Exclusive OR (XOR)
Shift 1
Generator polynomial
Exclusive OR (XOR)
Shift 2
Generator polynomial
Exclusive OR (XOR)
Shift 3
Shift 4
Generator polynomial
Exclusive OR (XOR)
Shift 5
Shift 6
Generator polynomial
Exclusive OR (XOR)
Shift 7
Shift 8
Generator polynomial
Exclusive OR (XOR)
07 (Function code)
H
Exclusive OR (XOR)
Shift 1
Generator polynomial
Exclusive OR (XOR)
Shift 2
Generator polynomial
Exclusive OR (XOR)
Shift 3
Generator polynomial
Exclusive OR (XOR)
Shift 4
Shift 5
Generator polynomial
Exclusive OR (XOR)
Shift 6
Shift 7
Shift 8
CRC value
App. - 53
The following show the example of 16-bit CRC (for MODBUS) calculation.
Packet example:
Station No. Function code
02
H
Procedure example of 16-bit CRC (for MODBUS) of a packet example above:
1111
1111
0111
1010
1101
0110
1010
1100
0110
0011
1010
1001
0100
0010
1010
1000
0100
0010
1010
1000
1000
0100
1010
1110
0111
1010
1101
0110
1010
1100
0110
0011
1010
1001
0100
0010
0001
07 41
H H
16-bit register (MSB)
1111 1111
0000
1111 1111
1111 1111
0000 0000
1111 1111
1111 1111
0000 0000
1111 1111
0111 1111
0011 1111
0000 0000
0011 1111
1001 1111
0100 1111
0000 0000
0100 1111
0010 0111
0001 0011
0000 0000
0001 0011
0000
0001 0011
0000 1001
0000 0000
0000 1001
0000 0100
0000 0000
0000 0100
1000 0010
0000 0000
1000 0010
0100 0001
0010 0000
0000 0000
0010 0000
1001 0000
0100 1000
0010 0100
12
H
16-bit CRC
12
H
Flag
1111
0010
1101
1110 1
0001
1111
1111 1
0001
1110
1111 0
1111 1
0001
1110
1111 0
1111 1
0001
1110
1111 0
1111 1
0001
1110
0111
1001
1100 1
0001
1101
1110 1
0001
1111
0111 1
0001
0110
0011 0
1001 1
0001
1000
0100 0
0010 0
0001 0
41
H
APPENDIXES
Calculating
procedure
1) to 2)
3) to 4)
5)
6)
7)
8)
App. - 53