shows the CRC-16 calculation of the slave address 02H and the function code 03H, yielding the
result D140H.
Note:
This example does not show the calculation for a complete MEMOBUS/Modbus command. Normally data would follow in the calculation.
Table C.4 CRC-16 Checksum Calculation Example
Description
Calculation
Overflow
Description
Calculation
Overflow
Initial Value (FFFFH)
1111 1111 1111 1111
Function Code 03H
0000 0000 0000 0011
Address 02H
0000 0000 0000 0010
XOR w result
1000 0001 0011 1101
XOR w initial value
1111 1111 1111 1101
Shift 1
0100 0000 1001 1110
1
Shift 1
0111 1111 1111 1110
1
XOR w A001H
1010 0000 0000 0001
XOR w A001H
1010 0000 0000 0001
XOR result
1110 0000 1001 1111
XOR result
1101 1111 1111 1111
Shift 2
0111 0000 0100 1111
1
Shift 2
0110 1111 1111 1111
1
XOR w A001H
1010 0000 0000 0001
XOR w A001H
1010 0000 0000 0001
XOR result
1101 0000 0100 1110
XOR result
1100 1111 1111 1110
Shift 3
0110 1000 0010 0111
0
Shift 3
0110 0111 1111 1111
0
Shift 4
0011 0100 0001 0011
1
Shift 4
0011 0011 1111 1111
1
XOR w A001H
1010 0000 0000 0001
XOR w A001H
1010 0000 0000 0001
XOR result
1001 0100 0001 0010
XOR result
1001 0011 1111 1110
Shift 5
0100 1010 0000 1001
0
Shift 5
0100 1001 1111 1111
0
Shift 6
0010 0101 0000 0100
1
Shift 6
0010 0100 1111 1111
1
XOR w A001H
1010 0000 0000 0001
XOR w A001H
1010 0000 0000 0001
XOR result
1000 0101 0000 0101
XOR result
1000 0100 1111 1110
Shift 7
0100 0010 1000 0010
1
Shift 7
0100 0010 0111 1111
0
XOR w A001H
1010 0000 0000 0001
Shift 8
0010 0001 0011 1111
1
XOR result
1110 0010 1000 0011
XOR w A001H
1010 0000 0000 0001
Shift 8
0111 0001 0100 0001
1
XOR result
1000 0001 0011 1110
XOR w A001H
1010 0000 0000 0001
Perform operations with next data (function code)
XOR result
1101 0001 0100 0000
CRC-16
1101 0001 0100 0000
D 1 4 0
(Lower) (Upper)
Continue from here with next data.
n
Response Data
Perform a CRC-16 calculation on the response message data as described above as a validation check. The result should match
the CRC-16 checksum received within the response message.
C.7 Message Format
384
YASKAWA TOEPYAIUPW01A YASKAWA AC Drive - U1000 iQpump Matrix Drive User Manual
