Knob to save value to item, og maybe something else

Hi… iam using habpanel to controle some z-wave radiator termostats, that works fine, have a knob where I can set the setpoint… thats fine…

But…

i have a “outdoor room” (don’t know the exact word in English) but a closed covered outdoor area with windows in it… and there I have installed electric heating… this is only something we use in special occasions, cause it is expensive to heat, I have a sonoff module running toasmota, that devices temperature af that room to habpanel, that works fine, and then I have another sonoff module that activates the electric heating, but, I want the sonoff temperature to do that, I can create a rule bases on the temperature, and that I think will work, but for my radiators I have a knob where I can ajust the set point, and want something similar to this, but I can’t figure out how to do it, I thing, I have to maybe bind the knob to a virtual item, to write the set point to this item, and then use this virtual item to the rule, but I don’t know if it is possible to create a virtual item, anyone having a good idea…?

this is one of the simplest things… just define an item without any binding or channel definition

Number myRoomTempSet "target temp [%.2f °F]"

and in sitemap

Setpoint item=myRoomTempSet minValue=41.0 maxValue=77.0 step=0,25

That was easy… I was thinking in that direction, but was not sure, that the item could “save” the value… I will try, thank you…

The state is saved by the event bus of openHAB (until restart).
If you want to save the item state so that openHAB will remember the state even if openHAB was restarted, you will have to use a persistence service.