Using RS485 port on CC100 with NodeRED

Steps to use the serial port on the CC100 with NodeRED in Docker.

  1. Disable the PLC Runtime

  2. The serial port on the CC100 is called /dev/ttySTM1 and has the correct permissions by default.


  1. Install Node-RED and attach the serial port in privileged mode.

docker run -d --name wago-node-red -d --privileged=true --user=root --network=host --device=/dev/ttySTM1:/dev/ttySTM1:rw -v node_red_user_data:/data nodered/node-red

  1. Open NodeRED GUI in browser at port 1880

5.Install the Modbus palette (node-red-contrib-modbus) in the palette manager

  1. Wire up your modbus slave device to the RS485 port on the CC100.

For example with the WAGO Modbus RTU coupler you would wire pin 3 and 8 to the D+/D- on the CC100 connector X11 as shown below.

  1. Now configure the Modbus Read serial connection as shown below using /dev/ttySTM1 as the com port.

On my device, I am reading an RTD module at address 0.

Run this to a debug node, and the temp sensor is publishing its readings as you would expect.

Here is the example flow.
CC100 Serial Port Example MB Read.json (1.9 KB)