Power Electronics VS65 Series Programming And Software Manual

VS65 SERIES MV SOFT STARTER
POWER ELECTRONICS
30
MODBUS COMMUNICATION
5.3.1. Modbus Function Code nº3. Registers reading.
This function code enables the Modbus controller (master) t read the data content registers
shown in the soft starter (slave). This function code allows only unicast addressing and it is not
possible to either broadcast or groupcast addressing.
This function code implementation enables the reading of up to 5 soft starter registers within the
same frame.
The following example frame shows how the master tries t read the content of 3 registers, which
show the current consumption per phase. The information attached in the question frame is the
following:
 Slave data access.
 Modbus function code (3 reading registers).
 Starting data address.
 Nº registers read.
 CRC- 16 code.
Soft starter (slave) response should contain the following fields:
 Slave data access.
 Modbus function code (3 reading registers).
 Nº of bytes to be read.
 Nº bytes / 2 registers
 CRC- 16 code.
Each register is composed of 2 bytes (2 x 8 bits = 16 bits). This is the standard length for all of the
soft starter registers.
Function Code nº3 operating example (Reading Registers).
In case reading the equipment current value is needed (nameplate) through communications.
This data corresponds to parameter [G2.1]. The frame transmitted is shown below:
Modbus
Address
Modbus
function code
Starting data
address
(40022)
Registers
number
CRC-16
OAH
03H
00H 15H
00H 01H
94 B5
Assuming the equipments current value is 110A. The Slave response would be:
Modbus
Address
Modbus
function code
Bytes number
Data
CRC-16
OAH
03H
02H
6EH
9CH 69H

Power Electronics VS65 Series Specifications

General

Brand	Power Electronics
Model	VS65 Series
Category	Controller
Language	English