Category: node-red

As part of my work with modbus I’ve created several tools that make testing node-red modbus flows easier. In particular I’ve created two dashboards . These dashboards are identical in appearance and they let you send modbus read and write commands form the browser. However the first dashboard interfaces directly with the modbus getter and write nodes whereas the second sends the commands via MQTT to  remote getter and setter nodes .

In the previous tutorial we looked at the modbus nodes and looked at how to read data from a Modbus server using node-red. In this tutorial we will look at writing data to a modus server using node-red.

Modbus is a de facto standard, truly open and the most widely used network protocol in the industrial manufacturing environment.-ref Modbus Faqs Because of its popularity there is a growing requirement for reading data and controlling Modbus devices over TCP/IP networks using node-red.

I have developed a few flows for third parties that have mainly involved decoding Modbus data. However I have never used Modbus in a live environment and needed to get familiar with the basics in order to develop and test these flows. Fortunately the people I worked with had a very good understanding of Modbus, but not of node-red, JavaScript and MQTT These are my working notes from my efforts to create these flows and in particular an MQTT to Modbus bridge. If you are new to Modbus you may find them useful.

When data is read from a file or network it is read byte by byte into a data buffer. Data Buffers are temporary storage used for transferring data. To work with binary data we will need access to these buffers.

This is a IOT data and topic logger similar to the python data and topic loggers that can be used for logging MQTT sensor and device data to log files either as a single file containing multiple topics or multiple files based on topic. It is controlled using a node-red dashboard making it much easier to use than the python loggers.