Network Variables not updating

acend
2022-09-13
2024-05-07
  • acend - 2022-09-13

    Hello Everyone,

    I'm quite new in Codesys 3.5 and I'm finding some issues on sharing Network variables between 2 PLC's.

    I'm using Codesys 3.5 SP18, and two Wago's PFC 100.

    From my PLC1, I can share a couple of Global variables block to the PLC2, but on the other direction I cannot.

    The procedure I'm following is the same for both PLC's: I have both PLC's in one project. Right click on the Global Variable block and Properties -> Network variables (config in the picture). Then on the other PLC I add a Network Variable List (Receiver), and I select the GVL that appears for selection.

    When I compile and run the PLC's, I can see what I think is the initial values of the variables, but they don't update, even if I force the variables on the source PLC.

    Note: I have tried several times this procedure, with different Identifiers and also using the Export&Import file procedure, with no success for the second PLC.

    Any idea why I can't make it work?

    Thank you in advance.

     
  • eschwellinger

    eschwellinger - 2022-09-13

    I would give this a try:
    instead of using 255.255.255.255
    use 192.168.x.255 as broadcast address in the network variables settings.
    Not every Linux OS does allow to send 255.255.255.255.

     

    Last edit: eschwellinger 2022-09-13
  • alex-wall - 2024-05-07

    This worked for me.
    I had four identical PLC's. Three of them worked just fine with 255.255.255.255 as the broadcasting address but the 4th would not update the variables. Changed it to 192.168.x.255 and everything worked.

     

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