Modbus Communication Protocol - Delta Electronics ASDA-B2 series User Manual

ASDA-B2

8.3 MODBUS Communication Protocol

When using RS-232/485 serial communication interface, each ASDA-B2 series AC servo
drive has a pre-assigned communication address specified by parameter "P3-00". The
computer then controls each AC servo drive according to its communication address.
ASDA-B2 series AC servo drive can be set up to communicate on a MODBUS networks
using on of the following modes: ASCII (American Standard Code for Information
Interchange) or RTU (Remote Terminal Unit). Users can select the desired mode along
with the serial port communication protocol in parameter "P3-02".
 Code Description:
ASCII Mode:
Each 8-bit data is the combination of two ASCII characters. For example, a 1-byte data: 64
Hex, shown as '64' in ASCII, consists of '6' (36Hex) and '4' (34Hex).
The following table shows the available hexadecimal characters and their corresponding
ASCII codes.
Character '0'
ASCII code 30H
Character '8'
ASCII code 38H
RTU Mode:
Each 8-bit data is the combination of two 4-bit hexadecimal characters. For example, a 1-
byte data: 64 Hex.
 Data Format:
10-bit character frame (For 7-bit character)
7N2
Start
0
bit
7E1
Start
0
bit
7O1
Start
0
bit
Revision September 2013
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' '2' '3'
31H 32H 33H
'9' 'A' 'B'
39H 41H 42H
1 2 3
7-data bits
10-bits character frame
1 2 3
7-data bits
10-bits character frame
1 3
2
7-data bits
10-bits character frame
Chapter 8 MODBUS Communications
'4' '5' '6'
34H 35H 36H
'C' 'D' 'E'
43H 44H 45H
Stop
4 5 6
bit
Even
4 5 6
parity
Odd
4 5 6
parity
'7'
37H
'F'
46H
Stop
bit
Stop
bit
Stop
bit
8-7