Mitsubishi FX3U Series User Manual page 49

FX Series Programmable Controllers
3U
User's Manual - MODBUS Serial Communication Edition
The following is a calculation example in the case where function code 07H is sent to station No. 2.
CRC error check procedure
(Load the register whose 16 bits are all "1")
02 (Station No.)
H
Exclusive OR (XOR)
Shift 1
Generator polynomial
Exclusive OR (XOR)
Shift2
Generator polynomial
Exclusive OR (XOR)
Shift3
Shift4
Generator polynomial
Exclusive OR (XOR)
Shift5
Shift6
Generator polynomial
Exclusive OR (XOR)
Shift7
Shift8
Generator polynomial
Exclusive OR (XOR)
07 (Function)
H
Exclusive OR (XOR)
Shift 1
Generator polynomial
Exclusive OR (XOR)
Shift2
Generator polynomial
Exclusive OR (XOR)
Shift3
Generator polynomial
Exclusive OR (XOR)
Shift4
Shift5
Generator polynomial
Exclusive OR (XOR)
Shift6
Shift7
Shift8
CRC value
Address field Function code
(02 ) (07
H
16-bit register (MSB)
1111 1111 1111
0000
1111 1111 1111
0111 1111 1111
1010 0000 0000
1101 1111 1111
0110 1111 1111
1010 0000 0000
1100 1111 1111
0110 0111 1111
0011 0011 1111
1010 0000 0000
1001 0011 1111
0100 1001 1111
0010 0100 1111
1010 0000 0000
1000 0100 1111
0100 0010 0111
0010 0001 0011
1010 0000 0000
1000 0001 0011
0000
1000 0001 0011
0100 0000 1001
1010 0000 0000
1110 0000 1001
0111 0000 0100
1010 0000 0000
1101 0000 0100
0110 1000 0010
1010 0000 0000
1100 1000 0010
0110 0100 0001
0011 0010 0000
1010 0000 0000
1001 0010 0000
0100 1001 0000
0010 0100 1000
0001 0010 0100
12
H
CRC (Error check)
) (41 ) (12
H
H
7 MODBUS Standard Commands
7.2 Frame Specifications
Carry 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
)
H
45
1
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