I'm using netvar-sender node to send network variable list to my Wago PLC. I have about 145 variables at this moment. When I add one more, the variable don’t arrive at the PLC anymore.
At first I thought a syntax error but then I deleted other (working) variables and it worked again. So I guess I reached a limit somewhere. I put a debug node behind the function that formats the array for sending it and everything looks ok and complete. PLC shouldn’t be the problem either so I’m guessing that the netvar-sender has reached his limit? Does anyone experienced this before? Anybody a suggestion for solution? There will be a lot of variables to add in the future so I’m kind of in trouble…
If you read this https://forge.codesys.com/forum/en/124/genmed-Network_Functionality_V23.pdf, you will see that the used udp package is limited to 256 bytes.
If I read correctly it could be possible to send more by splitting it up in multiple packages, but the Netvar-sender node doesn't support it. The easiest way for now is to use multiple list with different id's.
I started building my own version node-red-contrib-nvl, because the other node had some issues with negative real values. If you are interested, you can create an issue on the github page to dive deeper into the 256 byte limit. I could use some help in collecting sample data as I don't have a spare plc to play with at the moment.
