HMI communication getting lost

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1

Hello Folks,
We are having editable program of one of our old system in AS 2.7. Our customer want to have modification in the that program which very small change like making one of the variable retentive. As soon as we are making this change and download the program, HMI lost the connection with PLC. If we download the program without changing anything it works fine. Does any one have idea what could be the resolution ?

PLC: CP0292
HMI:4B1260.00-K07

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2

I guess this question is related to PVI Error 4063: Default error (_DownloadModule). Can you confirm it? So I can close this topic.

3

No this error occurred when we changed one variable retentive after that HMI and PLC communication get lost , if we revert the change and download the program communication works without issue, so we are not able to figure out what that magic is happening which dropping HMI and PLC communication

4

Hi,

it’s a long time ago since I used AS2.x and SGC cpu.

As I remember

  • the X20CP0292 doesn’t have volatile = DRAM memory - so if you say you made a variable retentive, does that mean that you put a remanent variable to the permanent storage, to make it coldstart-secure?
    (I’m asking because as I know every variable in a CP0292 is defaulted to remanent memory (= SRAM) by the compiler, independent if it’s marked as remanent inside the variable declaration or not.)
  • A permanent variable has to have a global scope - so was it already global before setting it to permanent, or was it a local one?

Maybe, the visualization object (because of using a 4B1260, I assume you’re using a VC3 visu?) has to be also recompiled, if a variable that is used inside the visu changes from remanent to permanent memory section, and/or maybe because of the scope of the variable has changed from local to global… but I really don’t remember, it’s too long ago, sorry.

Another question: what does “lost connection” mean? I understood it like “the PLC keeps running, but the visualization does not longer show anything” - is that right?
After the transfer and the broken display connection, where there any new errors / warnings inside the PLC logbook?

Best regards!
Alex