How to use values in different magnitudes coming from different sensors

Hey there!
I am pretty new to openHAB and quite impressed about the possibilites! Especially I like the idea to combine hardware from different vendors and technologies under one system.
However I ran across a small issue when I tried to combine energy-meter values from Fritz-AHA and Z-Wave (Fibaro) devices. Fritz-AHA give the values as number in unit [Wh] while the fibaro-plug gives energy value as float in unit [kWh]. When I do calculations later in rules I have to remember were the value came from (Fritz-AHA or Fibaro) to equalize the magnitude. This is not nice! Does openHAB offers something here, i.e. to set the magnitude in item configuration?

Many thanks in advance!


The device may offer some control in its configuration options, so I’d start with (sigh) reading the manual on it.

If there’s no option there, then some construct like:

Number temp1 {binding to read the Fritz-AHA}
Number temp2 temp1*1.0/1000

Something like that might work directly in ITEMS. (DK, just thinking…)

If still no joy, then do the math in your rules via:
var Fritz-converted = Fritz-AHA*1.0/1000

and combine with

Item Fritz-AHA changed

1 Like

Hi Bob!

Thanks for the reply. I checked manuals for both devices and there seems no such configuration option (or I missed it).

However I think the solution you drafted should do the job well for sure. I will try it on next occasion.

Thanks again!