Hello EAPOL

Which TIA Portal Version and which HMI device do you use?

What happens if you use a default F(x) control right out of the toolbox without making any changes to it?

Which Data do you try to visualize in the diagram? (Archive values or live values?)

Here is a basic application example, perhaps it helps:

https://support.industry.siemens.com/cs/ww/en/view/109481693

Bye Murof