Steps to use the serial port on the CC100 with NodeRED in Docker. Disable the PLC Runtime [image] The serial port on the CC100 is called /dev/ttySTM1 and has the correct permissions by default. [image] Install Node-RED and attach the serial port in privileged mode. docker run -d --name…

NodeRed CC100 Modbus RTU: please do the following steps: stop the container delete the container and volume start the container new enter the container and build node-red-contrib-modbus new docker stop node-red docker rm docker volume rm node_red_user_data docker run --name wago-node-red --p…

@Devlin_Hugo did you find a fix to get the serial communication working without node-red crashing? Edit: See here if this solves your issue. https://www.wago.community/t/how-to-using-pfc200-onboard-serial-port-with-node-red/68/5?u=stefsoma

Hi there @StefSoma , Sorry for taking a while to respond, quite a lot going on at the moment. I have managed to create a container with modbus rtu that does not crash. However the actual reads are not successful which is perhaps a configuration error on my side. I don’t believe so though as I have …

One thing you might check are the docker logs. If you open a terminal and after the NR container is created, type; docker logs [container-id] --follow Then configure the serial port in Node-RED and after the container crashes, there might be a clue posted to the log.

Thanks for the suggestion @WagoKurt , When I run the command and check file this is the message which appears each time I “inject” the modbus read node: 21 Jun 13:05:47 - [error] [modbus-read:65d2b5d11c21941e] Error: Client Not Ready To Read At State reconnecting I’m going to try using the advice …

A further update, if I remove the connection timeout in the Modbus Read node, the node in idles the green “active” state. I then trigger the modbus rtu read in Node-RED and now I get an error which says “Error: Port Not Open”. This seems to point to the fact that there’s some type of configuration …

I can confirm the container stops when using modbus read with the serial port STM1 on CC100/FW25.

@WagoKurt I’m trying my exact same setup /config as for another wago C100 that’s working with both TCP and serial node-red-contrib-modbus. Last time I ran npm rebuild --build-from-source. After that (and making sure the modbus wiring and EOL resistor were in place it worked). However, the npm rebuil…

Please check the FW for both CC100’s. In the short term, it may be necessary to install older FW.

@WagoKurt Thanks for you reply. Both my CC100 have 03.09.07(21) firmware. So that is not the issue it seems.

Interesting. Can you please check the versions of the node-red-contrib-modbus and Node-RED?

Using RS485 port on CC100 with NodeRED

Node-RED

MikePsaltis January 7, 2026, 3:20pm 34

Thanks, Damian. I just tried this on a 751-9301 (FW28) with your image and it worked!

Accessing the CC100 RS-485 interfaces from Linux while CODESYS is using them

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Using RS485 port on CC100 with NodeRED

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