Item has maximum value however ON/OFF switch does not recognize

Hey folks,

I have configured a dimmable (hope that is right) light. However since the light at 100% is rather bright I have configured that maximum to be 30%, so that when I toggle the slider of the dimmer 30% is the max it can go to.

In my automatic rules I am not using the dimmer with % but rather the ON/OFF function of a switch. However when using this in combination with the dimmer the light always goes up to 100%. When I then manually access the dimmer item it updates itself down to 30%.

Is there a way that the maximum configured value gets properly respected or what am I overlooking.

Cheers & thanks

What maximum value? It sounds like you’ve configured a UI widget to have a maximum. That will not constrain the underlying Item; if you command that ON the standard openHAB result is 100%.

Welcome Torsten :slight_smile:
As rossko57 already pointed out, an “ON” command is translated in the background to a “100%” command for dimmer items.

If your device has an option of “set value after power-on” or similar, that usually only affects the behaviour after a real power-up of the device.

Your way forward can be to use an additional item of type switch as a proxy item. This would be the switch you present to the user. Then add a rule that triggers depending on the proxy item and use a “<your-slider-itemname-here.sendCommand(30)” as action.
In case you have groups for your lights, place the proxy item in the group.

No! If sending an ON to a dimmer Item, the Dimmer Item will send the command ON to the channel.
It depends on the hardware what will happen then.
There may be some bindings which will do a translation to 100 silently, but that is not true for all bindings.

E.g. for my knx bus, if sending ON to the dimmer, knx sends a real ON command to the ON/OFF part of the dimmer, which then will result in a dim to 80%, due to the fact, that I set up my dimmers to go to 80% when switched ON. (Even if the dimmer is set to 100% it will dim to 80% after receiving the ON command).

Thanks for the clarification, I did not know yet is depends on the binding. Info stored :slight_smile:

The way forward with the rule should function anyway, independent of what a binding does with the ON command.


thanks for the replies. The config is set on item level - indeed configuration on UI widget level would be pointless. I am using a homeatic powerplug and thus the homeatic binding. Based on Udo’s comment I will check if I can configure something in the homeatic UI to limit it there to a maximum value so that the trigger gets limited on that end.

Will post an update once tried.

To add the solution. I configured a trigger rule in homeatic itself to react in case the Wallplug gets triggered and set to 100% (which is the setting for SWITCH ON) and to reduce it to 30%. In this case this setup is fine as I will not wanna dim these lights up to 100% as they are too bright. However if I have a light that I actually want to bright up I either have to set a slider dimmer to 99% (as max value to avoid triggering the 100%) or I will have to look for a different solution

Comment - note that openHAB’s autoupdate feature will also interpret ON command and issue a “100%” state update prediction for the Item.

If the real device responds in some other way, it may come back with its real status a while later (via the binding) and update the state again to something else.

You didn’t tell us exactly what you did - setting UI options in an Item’s metadata does not mean other parts of openHAB - autoupdate, bindings, rules - are constrained in any way by those options.
In short, I don’t think that does what you think it should.
End result - yes you will have to use other methods like rules for the wanted limitation.