KEYENCE N-410 - Manual (Page 150)

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6
Calculating Checksums
A checksum can be appended to read data as it is being transmitted (The checksum will not be
appended to commands or replies).
The checksum allows you to check if RS-232C communications have become corrupted. By
using the PASS/RTRY or ACK/NAK protocols, an automatic RTRY or
can be sent if the
checksum does not match. Settings should be handled through "Protocol settings" on the setting
software (This cannot be done when using a PLC link).
Checksum calculation range and location
The checksum is calculated using all characters that are not a part of the header or the delimiter
and is then appended immediately after the delimiter.
CC= checksum (2 ASCII characters)
• When an ID number is appended
• When an ID number is not appended
NAK
P mm - Header Read data % Delimiter cc
P 01 - Header ERROR % Delimiter cc
nnnn
0009
Header Read data Delimiter cc nnnn
Header AB12 Delimiter cc 0004
Header AB12 Delimiter cc 0004