Delta Electronics ASDA-B2 series User Manual page 279

Chapter 8 MODBUS Communications
LRC Check
End 1
End 0
RTU Mode:
Command message:
Slave Address
Function
Starting data
address
Number of data
(In Word)
Number of data
(In Byte)
Content of 1st data
Content of 2nd
data
CRC Check Low
CRC Check High
Please note that a silent interval of more than 10ms is required before and after data
transmission in RTU mode.
LRC (ASCII Mode):
LRC (Longitudinal Redundancy Check) is calculated by summing up, module 256, the
values of the bytes from ADR to last data character then calculating the hexadecimal
representation of the 2's-complement negation of the sum.
Example
STX
ADR
CMD
Starting data address
Number of data
LRC Check
8-12
info@varitel.com - www.varitel.com - Tel. (54) 11-4243-1171 / Fax: (54) 11-4292-7545
Manuel Baliña 456, Lomas de Zamora (B1832CCJ) Buenos Aires, Argentina.
VARITEL INGENIERIA ELECTRONICA S.A.
'1'
'3'
(0DH)(CR)
(0AH)(LF)
01H
10H
01H (Upper bytes)
12H (Lower bytes)
00H (Upper bytes)
02H (Lower bytes)
04H
0BH (Upper bytes)
B8H (Lower bytes)
00H (Upper bytes)
00H (Lower bytes)
FCH (Lower bytes)
EBH (Upper bytes)
':'
'7'
'F'
'0'
'3'
'0'
'5'
'C'
'4'
'0'
'0'
'0'
'1'
'B'
'4'
Response message:
Slave Address
Function
Starting data
address
Content of data
(In Word)
CRC Check Low
CRC Check High
ASDA-B2
01H
10H
01H (Upper bytes)
12H (Lower bytes)
00H (Upper bytes)
02H (Lower bytes)
E0H (Lower bytes)
31H (Upper bytes)
Revision September 2013