Dear all,

I have an analogous problem with the "Value Change" event of an HMI Tag, in that the event is triggered just ONCE!

This HMI Tag is connected to a PLC tag (whose value changes every, say, 30 sec).

I would like to use the event to execute a VB Script, which indeed gets executed once. But I have to switch off/on the HMI to have it re-executed.

Also, if instead of the script, I just increment another tag with the "Value Change" event, the tag gets incremented ONCE. Again I have to switch off/on the HMI to have it incremented again.

Why???

Thanks!!

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Split from HMI Tag's "Value Change" -event doesn't work.

Hello Alberto,

acquisition mode of the trigger tag is cyclic continuous and the PLC tag changes state from 0 to 1 and after 30s from 1 to 0?

What happens when you use an IO field with the trigger tag, can you see it switching, is the script then called?

Regards,

Frink

Dear prof. Frink,

thanks for your answer.

Yes, the HMI tag is linked to a PLC tag that switches 0->1 and after 30 sec 1->0 an so on.

The acquisition cycle is continous (200 ms).

Investigating a bit more deeply, it turns out that the problem is the kind of event I want to trigger, namely ActivateScreen "Root screen", 0.

If I link the "Value change" event to the activation of another screen, different from the Root, it works!

Also the event ActivatePreviousScreen does not work...

So, how can I go back to the Root screen when an HMI tag changes value?

Thanks!

Find out...!

On a real HMI everything works smoothly! (I was using the simulator...)