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Chapter 8 MODBUS Communications|ASDA-AB Series
8-12 Revision January 2009
RTU Mode:
Command message: Response message:
ADR 01H ADR 01H
CMD 03H CMD 03H
02H (Upper bytes)
Starting data
address
00H (Lower bytes)
Number of data
(Count by byte)
04H
00H
00H (Upper bytes)
Number of data
(Count by word)
02H
Contents of starting
data address
0200H
B1H (Lower bytes)
CRC Check Low C5H (Lower bytes)
1FH (Upper bytes)
CRC Check High B3H (Upper bytes)
Contents of second
data address
0201H
40H (Lower bytes)
CRC Check Low A3H (Lower bytes)
CRC Check High D4H (Upper bytes)
Command code: 06H, write 1 word
For example, writing 100 (0064H) to starting data address 0200H of ASDA-AB series with address 01H.
ASCII Mode:
Command message: Response message:
STX ‘:’ STX ‘:’
‘0’ ‘0’
ADR
‘1’
ADR
‘1’
‘0’ ‘0’
CMD
‘6’
CMD
‘6’
‘0’ ‘0’
‘2’ ‘2'
‘0’ ‘0’
Starting data
address
‘0’
Starting data
address
‘0’
‘0’ ‘0’
‘0’ ‘0’
‘6’ ‘6’
Content of data
‘4’
Content of data
‘4’
‘9’ ‘9’
LRC Check
‘3’
LRC Check
‘3’
End 1 (0DH)(CR) End 1 (0DH)(CR)
End 0 (0AH)(LF) End 0 (0AH)(LF)