Delta ASDA-B2-F Series User Manual page 196

ASDA-B2-F
LRC and CRC Transmission Error Check
The error check of ASCII mode is LRC (Longitudinal Redundancy Check) and CRC (Cyclical
Redundancy Check) is for RTU mode.
LRC (ASCII Mode):
Slave Address
Function
Start Data Address
Data Number
LRC Check
The calculation of LRC is to add up all the byte, round down the carry and take 2's complement.
For example: 7FH + 03H + 05H + C4H + 00H + 01H = 14CH, round down carry 1 and take 4CH.
2's complement of 4CH is B4H.
September, 2015
Start
End 1
End 0
':'
'7'
'F'
'0'
'3'
'0'
'5'
'C'
'4'
'0'
'0'
'0'
'1'
'B'
'4'
(0DH)(CR)
(0AH)(LF)
Communications
8
8-11