Codesys 2.3 Node-red Communication

Dear All!

At first thanks the possibility to connect to the community.
Maybe my topic is not really the latest technology but I have to solve somehow.
I would like send bits and words from 750-841 to Node-red which is running on raspberry (and reverse) . The sending is managed (using network variables) but I can not receive data from Node-red. I followed up @WagoKurt’s videos in this topic (ecockpit) but at the end I failed :confused:
Could you give some hints?
Thank you in advance!

Hello, do you have the possibility to do frame capture in the rPI ?
If so can you check if you have the right NVL number ?
Also in your project do you have 1 list for receiving and another list for sending ?
What IP address you have put in the NVL network parameters ?

I tried to upload some screenshots but the system does not let it. On codesys side I have to table one is for sending List indetifier 1 and a receiving list indetifier 3. I am using port 1202 If I modify any of the variables in codesys sender NVL it changes in node-red. After I make some modification on the data and send back to codesys NVL receiver table. It changes in node-red but nothing changes on the other side. Although I changed the tables but I did not change the ID because I do not know where is it in 2.3 Maybe this is the problem.

what about the ip addresses ?
Are you using ? or abc.def.ghi.255 ? or abc.def.ghi.jkl ? or multicast ip ?

These are the setting that I am using int he project

Make sure the NVL port is exposed and there is no firewall blocking it.

What does it mean to expose NVL port. I try to make communication between PLC and Raspberry. They are on the same network. I also try to make communication my PC (installed node red) and PLC. I created the necessary exception to UDP communication (Incoming and outgoing rules) but I got the same result. On the raspberry there is no firewall. I just install a simple linux on it.

Are you running Node-RED in a Docker-environment on the Raspberry? If so, you need to allow the UDP-ports set up in the NVL in CS2.3.


Also, I find the module “node-red-contrib-nvl” better and more up to date than the “node-red-contrib-netvar” which is used in WagoKurt’s tutorial.

if you need to open other container port after having setting everything up, here is a how to for this:

No. I am not using docker. Should I?

I find it easier to manage, but you don’t have to…

Have you tried the library I mentioned?
You can copy/paste the content of the NVL file directly into the node, enter the list id and connect it to the UDP listener.

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Sorry for my late respond. Yes I tried it and it is working now. Thanks for the hint!

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