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Get Unslave v.3.0.1 How to get Started
Demonstrates Unslave UI with Modbus request frames

The Perfect Modbus RTU/TCP Slave Simulator

Unslave is a software tool that allows you to easily simulate any number of Modbus RTU or Modbus TCP devices.

In addition, Unslave cleanly displays and logs all requests, which makes debugging Modbus networks a breeze.

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Example of Unslave configuration with multiple Modbus RTU slaves

Powerful Configuration and API

Add any number virtual Modbus slaves, registers and even simulate Modbus exceptions by editing a simple JSON file.

Alternatively, you can use the HTTP API provided by Unslave to update configuration at runtime

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Download and use Unslave for free, forever.


Download, unzip and you are ready to go.


Simulate any Modbus network you can imagine. HTTP API support.


The configuration process only takes a few seconds.

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