Chapter 8 MODBUS Communications| ASDA-A&A+ Series
8-12 Revision April 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-A and ASDA-A+ series with
address 01H.
ASCII Mode:
Command message: Response message:
STX ā:ā STX ā:ā
ā0ā ā0ā
ADR
ā1ā
ADR
ā1ā
ā0ā ā0ā
CMD
ā6ā
CMD
ā6ā
ā0ā ā0ā
ā2ā ā2'
ā0ā ā0ā
Starting data
address
ā0ā
Starting data
address
ā0ā
ā0ā ā0ā
ā0ā ā0ā
ā6ā ā6ā
Content of data
ā4ā
Content of data
ā4ā
ā9ā ā9ā
LRC Check
ā3ā
LRC Check
ā3ā
End 1 (0DH)(CR) End 1 (0DH)(CR)
End 0 (0AH)(LF) End 0 (0AH)(LF)
Call 1(800)985-6929 for Sales
Call 1(800)985-6929 for Sales