Fcs Calculation - Omron V530-R150 Operation Manual

FCS Calculation

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 send-
ing data can be checked for errors. Refer to Appendix B FCS
Check Program Examples (BASIC) .
(e.g.) Reading data:ABCDEFG
The sending data is as shown below.
Header
Calculation
A
B
C
D
E
F
G
Result
56
Reading data
ASCII
code
41 0100
XOR
42 0100
XOR
43 0100
XOR
44 0100
XOR XOR
45 0100
XOR
46 0100
XOR
47 0100
0100
4
p. 181
FCS
0001
0010
0011
0100
0101
0110
0111
0000
Converted into hexadecimal
0
and used as ASCII codes.
Section 4-4
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