Omron V400-H111 - Manual (Page 86)

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V400-H111/211
User’s Manual
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Appendices
FCS Calculation Method
■ FCS Calculation Method
The FCS (Frame Check Sequence) is the result of taking the XOR for each byte
between the header and footer (8 bits) and converting it to 2 characters of ASCII.
The FCS can be attached to output data to improve the reliability of communications.
Each time data is received, the host calculates the FCS and checks it against the FCS
attached to the sent data so that the send data can be checked for errors.
■ Calculation Example for Sending FCS
Sample read data: ABCDEFG
The details of the read data and calculation method are as follows:
• Read data
Header Footer
Read data FCS
• Calculation method
Read data ASCII Hexadecimal
Conversion to
ASCII:
Conversion to
hexadecimal
values
Obtaining the
exclusive OR:
Conversion to
ASCII:
FCS data: 40