Omron V530-R150E-3 -, Operation Manual

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FCS Calculation
Section 4-4
4-4 FCS Calculation
FCS (Frame Check Sequence) can be attached to output data to
improve communications. (For normal communications only). FCS is
the result of taking the XOR for each byte between header and footer
(8 bits) and converting to 2-character ASCII codes.
Each time data is received, the host link calculates the FCS and
checks it against the FCS attached to sending data so that sending
data can be checked for errors. Refer to Appendix B FCS Check Pro-
gram Examples (BASIC).
“
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(e.g.) Reading data: ABCDEFG
The sending data is as shown below.
Header Footer
Reading data FCS
Calculation
ASCII
code
A
XOR
B
XOR
C
XOR
D
XOR XOR
E
XOR
F
XOR
G
Result
Converted into hexadecimal
and used as ASCII codes.
4 0
41
42
43
44
45
46
47
0100
0100
0100
0100
0100
0100
0100
0001
0010
0011
0100
0101
0110
0111
0100 0000