The all in one Modbus TCP and Serial contribution package for Node-RED.

Usage no npm install needed!

<script type="module">
  import nodeRedContribModbus from '';


Platform Node-RED Contribution Modbus Financial Contributors on Open Collective NPM version ES_Sourdce_Version ES_Deploy_Version NodeJS_Version Standard - JavaScript Style Guide NPM download Build Status Codacy Badge Gitpod Ready-to-Code


The all in one Modbus TCP and Serial contribution package for Node-RED.


Node-RED contribution package for Modbus

Based on modbus-serial with TCP, C701, Telnet, Serial, RTU buffered, and ASCII

  • stress tested with Node-RED v1.0.4 and Node.js LTS
  • works with queueing per unit and round robin scheduling

Node-RED v1.x versions:

  • Node.JS 16.x will be supported with v6.+
  • Node.JS 14.x is supported with v5.14.+
  • Node.JS 12.x is supported with v5.x
  • Node.JS 10.x is supported with v5.x

Node-RED v0.x versions:

  • Node.JS 10.x is supported with v4.x
  • Node.JS 8.x is supported with v3.x
  • Node.JS 6.x is supported with v2.x
  • Node.JS 4.x is supported with v1.x

If you like that contributor's package for Modbus, then please give us your star at GitHub !


Run the following command in the root directory of your Node-RED install

npm install node-red-contrib-modbus

Run the following command for global install

npm install -g node-red-contrib-modbus

try these options on npm install to build, if you have problems to install

--unsafe-perm --build-from-source

modbus-serial, serialport and jsmodbus

The serialport optional dependency is just to list all ports on your system in the client configuration. It is not the serialport version to work with Modbus at runtime. For that check the modbus-serial or jsmodbus package.json, please! The modbus-serial supports and works for TCP connections in that package, too. The jsmodbus package is just to provide a simple Modbus Server node. All Modbus commands running on modbus-serial.

TCP or Serial testing

If you get in trouble with TCP connections, then check and test with just modbus-serial first, please!

If you get in trouble with Serial connections, then check with just serialport first, please!


To update the dependencies or the whole package, you have just to install again.

npm show node-red-contrib-modbus@* version

To get a special version please set the version with @M.M.F:

npm install node-red-contrib-modbus@3.6.1

or global by

npm install -g node-red-contrib-modbus@3.6.1

How to use

Flow Example


Debug will be activated by starting Node-RED with debug mode:

DEBUG=contribModbus*,modbus-serial node-red -v



see Wiki pages to get more options in detail


Let's work together! Contributors are welcome. Please, for the repo and send your pull requests from your repo to our develop branch or open issues while you're testing!

For Developers

See the scripts of the package and the additional Shell scripts to clean, update, or upgrade this NPM package.

  • dev-link (local testing with Node-RED)
  • testing (unit, integration)
  • coverage
  • docs generation
  • standard-version alpha, beta, release
  • git-flow

For Testers

Report issues, share your experiences, record tutorials, write Wiki articles and Blogs to share more about this package, please!


since April 2016 by Klaus Landsdorf and Community Driven



Code Contributors

This project exists thanks to all the people who contribute. [Contribute].

Financial Contributors

Become a financial contributor and help us sustain our community. [Contribute]



Support this project with your organization. Your logo will show up here with a link to your website. [Contribute]