If you are wanting to get data out of HE about the devices connected to the HE hub (or even virtual devices), you just need to "install" a copy of the Maker API built-in app, add the devices to the list in the Maker API configuration:
Then copy some of the URL's in the main app screen:
The Device Info includes the current state, as well as other information that may be useful for different purposes such as interfacing with HE dynamically...
So, depending on what is required in PRTG, hopefully this will help.
Simon
