User`s manual

Chapter 4 Communications Control
4-17
4
 BCC
BCC is a horizontal parity check code used to improve the reliability of data
communication. The exclusive OR is executed from the header ( )to final
characters of communication data, and the exclusive OR in 8-bit data is
converted to 2-character ASCII code. The sensor head is used to compare the
exclusive OR from the header to final characters of the message received, and
check if the exclusive OR coincides with the transmitted value of the PC. If
the BCC at the time of transmission differs from that after reception, it
indicates that some error has occurred in the message while in transmission.
In the case of omitting BCC calculation, accommodate (2AH, 2AH) in
the BCC. If data is transmitted with the BCC omitted, the BCC in the
response data will be (2AH, 2AH) as well.
BCC Creation Example
＊ ＊
＊ ＊
%
2-character BCC
% E E # R M D 3 E6
CR
%
E
E
#
R
M
D
3
End character of
communication data
Header
Exclusive logical sum (XOR) of received message is
calculated.
ASCII
H25
H45
H45
H23
H52
H4D
H44
H33
H6E
6 E
BCC
(H)
BCC
(L)
(H36) (H45)