Number definition with implicit calculation

I am using the following expression to create an item for the free HDD space on my enigma2 satellite receiver:
Number VuSzHddFree “HDD Frei [%.1f GB]” ( VuSz ) { http="<[http://bm750/web/about:300000:REGEX(.?(.?) GB.*)]"}
This works perfect, however the value is wrong. There is an offset of about 14GB which the receiver reports to what is really available for recording.
Can i subtract a fixed offset value in my number definition or do i have to create another item for that?


I assume you need an Item that includes the correct value, not just to display the correct value. In that case what you would need to do is replace your REGEX transformation with a JS transformation and extract the value and do the math inside a JavaScript function.

If all you want is to display the correct value, you can use a JS transformation to do the math in the Item’s label.

Or, as you indicate, you could create a Proxy Item and a Rule to do the math for you.