KEYENCE BL-700 Series - Manual (Page 152)

Appendices
138
Appendices
Appendix J Checksum Calculation Method
You can add a checksum to transmitted data. (The checksum cannot be added to a
command or a response to a command.)
Adding a checksum enables incorrect data translation to be detected in the RS-
232C communication. If the checksum does not match when the PASS/RTRY or
ACK/NAK protocol is used, modify the program so that the “Request to resend”
(RTRY or <NAK>) command is sent to the BL-700. To set the checksum, use the
“PROTOCOL SETUP” screen of the BL-700 setup software. (The checksum
cannot be added when the PLC link is used.)
Checksum calculation range and the position to add checksum
The checksum calculation is performed with all characters except for the header
and delimiter. The checksum is added immediately before the delimiter.
CC = Checksum (2 ASCII code characters)
• Read data
• When using the data addition function
• Test mode
Heade Read Data CC Delimiter
Header Code Type
Label
Orientation
Read Data
Decode
Count
Scan Count Delimiter : : : / CC
Header Read Data Reading Rate or Decode Count Delimiter CC : :