User manual

ASDA-A User Manual Chapter 8 MODBUS Communications
© DELTA ELECTRONICS, INC. ALL RIGHTS RESERVED 4th Edition 2005/11/30, HE03
8-9
ADR (Communication Address)
The valid communication addresses are in the range of 1 to 254.
For example, communication to AC servo drive with address 16 decimal:
ASCII Mode: ADR=’1’,’0’ => ‘1’=31HΔ’0’=30H
RTU Mode: ADR = 10H
CMD (Command Codes) and DATA (Data Characters)
The format of data characters depends on the command code. The available command codes and
examples for AC servo drive are described as follows:
Command code: 03H, read N words. The maximum value of N is 10.
For example, reading continuous 2 words from starting address 0200H of AC servo drive with address 01H.
ASCII Mode:
Command message: Response message:
STX ‘:’ STX ‘:’
‘0’ ‘0’
ADR
‘1’
ADR
‘1’
‘0’ ‘0’
CMD
‘3’
CMD
‘3’
‘0’ ‘0’
‘2’
Number of data
(Count by byte)
‘4'
‘0’ ‘0’
Starting data
address
‘0’ ‘0’
‘0’ ‘B’
‘0’
Contents of starting
data address
0200H
‘1’
‘0’ ‘1’
Number of data
‘2’ ‘F’
‘F’ ‘4’
LRC Check
‘8’
Contents of second
data address
0201H
‘0’
End 1 (0DH)(CR) ‘E’
End 0 (0AH)(LF)
LRC Check
‘8’
End 1 (0DH)(CR)
End 0 (0AH)(LF)
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)