Communication Parameter Settings; Modbus Communication Protocol - Delta ASDA-B3 Series User Manual

ASDA-B3
9.2 RS-485 communication parameter settings
The required parameters for a single servo drive connection are: P3.000 (Address), P3.001
(Transmission speed), and P3.002 (Modbus communication protocol). P3.003 (Modbus
communication error handling), P3.004 (Modbus communication timeout), P3.005 (Modbus
communication), P3.006 (Digital input (DI) control switch), and P3.007 (Modbus communication
response delay time) are optional settings. Refer to Chapter 8 for detailed descriptions of the
relevant parameters.

9.3 Modbus communication protocol

There are two modes of Modbus network communication: ASCII (American Standard Code for
Information Interchange) and RTU (Remote Terminal Unit). You can set the communication
protocol (ASCII or RTU) with P3.002 according to your requirements. The servo drive also
supports these functions: reading multiple words (03H), writing single word (06H), and writing
multiple words (10H). Refer to the following descriptions.
Note: the servo drive does not support the broadcast mode.
Code description
ASCII mode:
In ASCII mode, data is transmitted in ASCII (American Standard Code for Information
Interchange) format. For instance, to transmit "64H" between the master and slave, the ASCII
codes "36H" and "34H" are sent to represent "6" and "4" respectively.
The corresponding ASCII codes for the numbers 0 to 9 and the characters A to F are as follows:
Symbol
ASCII code
Symbol
ASCII code
RTU mode:
In RTU mode, each data frame consists of an 8-bit character (hexadecimal), which is more
efficient than ASCII mode for data transmission because it can be done without code
interchange. For instance, when transmitting "64H" between the master and slave, simply send
"64H".
'0' '1' '2'
30H 31H 32H
'8' '9' 'A'
38H 39H 41H
Modbus Communication
'3' '4' '5'
33H 34H 35H
'B' 'C' 'D'
42H 43H 44H
9
'6' '7'
36H 37H
'E' 'F'
45H 46H
9-3