Omron EasySpeed 3G3JV Series - BCC Calculation Example; Communications Data

Chapter 2
2-3
CompoWay/F Communications Procedures
■ BCC Calculation Example
The BCC (Block Check Character) is determined by calculating the exclusive OR of the bytes from
the node number through ETX. The 8-bit result is written to the BCC byte at the end of the frame.
■ Communications Data
Communications
protocol
Set values Negative
values
Data
Compoway/F 8-digit hexadecimal 2's comple-
ment
The decimal point is removed and the result is con-
verted to hexadecimal.
Example conversion: 105.0
→ 1050 → H'0000041A
STX Node number
Sub-address SID
Command text
ETX
BCC
The result of the calculation (H'35) is written to the BCC byte.
The + symbols indicate exclusive OR operations.
H'02 0 (H'30)
0 (H'30) 0 (H'30)
0 (H'30)
0 (H'30)
0 (H'30)
5 (H'35)
0 (H'30)
3 (H'33)
H'03 H'35
BCC = H'30 + H'30 + H'30 + H'30 + H'30 + H'30 + H'35 + H'30 + H'33 + H'03 = H'35