MODBUS RTU, TCP, ASCII data parser

Latest version: 5.0.1 build 313. March 20, 2025.

MODBUS is a serial communications protocol for use with programmable logic controllers (PLCs). Simple and robust, it has since become a de facto standard communication protocol, and it is now a commonly available means of connecting industrial electronic devices.

Our MODBUS RTU/ASCII and MODBUS TCP plugin can work in different modes:

• MODBUS master - the plugin sends MODBUS requests and processes the responses. In this mode, the program operates in the Master mode. You should know all request parameters and describe all expected response items.
• MODBUS [Slave] - the program acts as a MODBUS slave device and sends responses from another MODBUS master PLC or device. This mode is helpful if you need to send data from a PLC to a host computer at any time using the "Write" request.
• MODBUS [Passive] - the program processes all requests and responses of other devices communicating over an RS485 bus and then exports decoded data.

This module has the following features:

• Can send valid data requests to any MODBUS-compatible device.
• Can send requests with all major MODBUS functions.
• Calculates and verifies checksum for all data packets.
• Can request bytes, word, double words, and single registers, bits, interpret a sequence of bytes as strings.
• Can poll several MODBUS devices by a custom interval.
• Can flexibly parse all received data packets and extract register's values.

How to enable this plugin

The figure below shows how to select the plugin on the "Modules" page.

Fig.1. Selecting the plugin.

How to configure the plugin

The figure below shows how to configure the plugin. Please, look at the documentation for the full description of all settings.

Fig.2. Configuring the plugin.

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