YASKAWA GPD 506/P5, Technical Manual

Page: 34 / 66

The Message Format 6-13
CRC-16 Calculation Example:
A two byte message for a read-out of a
specified coil status is as follows.
0000 0010 Slave Address = 2
0000 0111 Function Code = 7
The actual CRC calculation would look like
this:
CRCTMP FLAG
1111 1111 1111 1111 Initial Value
0000 0010 Slave Address
1111 1111 1111 1101 Result of EX OR
0111 1111 1111 1110 1 Shift #1
1010 0000 0000 0001 CRC-16 Lower 16
1101 1111 1111 1111 Result of EX OR
0110 1111 1111 1111 1 Shift #2
1010 0000 0000 0001 CRC-16 Lower 16
1100 1111 1111 1110 Result of EX OR
0110 0111 1111 1111 0 Shift #3
0011 0011 1111 1111 1 Shift #4
1010 0000 0000 0001 CRC-16 Lower 16
1001 0011 1111 1110 Result of EX OR
0100 1001 1111 1111 0 Shift #5
0010 0100 1111 1111 1 Shift #6
1010 0000 0000 0001 CRC-16 Lower 16
1000 0100 1111 1110 Result of EX OR
0100 0100 0111 1111 0 Shift #7
0010 0001 0011 1111 1 Shift #8
1010 0000 0000 0001 CRC-16 Lower 16
1000 0001 0011 1110 Result of EX OR
0000 0111 Function Code
1000 0001 0011 1001 Result of EX OR
0100 0000 1001 1100 1 Shift #1
1010 0000 0000 0001 CRC-16 Lower 16
1110 0000 1001 1101 Result of EX OR
0111 0000 0100 1110 1 Shift #2
1010 0000 0000 0001 CRC-16 Lower 16
1101 0000 0100 1111 Result of EX OR
0110 1000 0010 0111 1 Shift #3
1010 0000 0000 0001 CRC-16 Lower 16
1100 1000 0010 0110 Result of EX OR
0110 0100 0001 0011 0 Shift #4
0011 0010 0000 1001 1 Shift #5
1010 0000 0000 0001 CRC-16 Lower 16
1001 0010 0000 1000 Result of EX OR
0100 1001 0000 0100 0 Shift#6
0010 0100 1000 0010 0 Shift #7
0001 0010|0100 0001 0 Shift #8
1 2 | 4 1
|
|
|
After calculating the CRC-16 upper and lower
values they are inserted into the message
format as shown below.
0000 0010 Slave Address = 2
0000 0111 Function Code = 7
0100 0001 CRC-16 Lower = 41h
0001 0010 CRC-16 Lower = 12h
CRC-16
(Upper 8)
CRC-16
(Lower
8)