Delta Electronics ASDA-B Series User Manual page 247

Chapter 8 MODBUS Communications|ASDA-B Series
RTU Mode:
Command message:
ADR
CMD
Starting data
address
Content of data
CRC Check Low
CRC Check High
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.
For example, reading 1 word from address 0201H of the ASDA-B series AC servo drive with address 01H.
STX
ADR
CMD
Starting data address
Number of data
LRC Check
End 1
End 0
01H+03H+02H+01H+00H+01H = 08H, the 2's complement negation of 08H is F8H.
Hence, we can know that LRC CHK is 'F','8'.
8-12
01H
06H
02H (Upper bytes)
00H (Lower bytes)
00H (Upper bytes)
64H (Lower bytes)
89H (Lower bytes)
99H (Upper bytes)
':'
'0'
'1'
'0'
'3'
'0'
'2'
'0'
'1'
'0'
'0'
'0'
'1'
'F'
'8'
(0DH)(CR)
(0AH)(LF)
Response message:
ADR
CMD
Starting data
address
Content of data
CRC Check Low
CRC Check High
01H
06H
02H (Upper bytes)
00H (Lower bytes)
00H (Upper bytes)
64H (Lower bytes)
89H (Lower bytes)
99H (Upper bytes)
Revision January 2009