KNX Binding - Percentage vs ON/OFF - ON/OFF not working

Hi there

My ventilation unit is hooked up to an 0-10V analog actor (MDT AIO) and the 230VAC is supplied by an MDT AMI switch.
So that means the unit is “controlled” by two different actor, don’t know if that matters but just giving the info.

The ventilation unit should not be switched off but I made it possible anyway by just switching of the supply line via the AMI.

However, when I slide the dimmer to 0% in the relay does not turn off. If I create a switch in my sitemap linking to the dimmer item I can turn off the relay so the config regarding the KNX part seems to be okay…

Default item=dimmer_Pct_Ventilatie
		Switch item=dimmer_Pct_Ventilatie
    	Text item=dimmer_Pct_Ventilatie

Another thing that bothers me, do I really need to define a seperate item for showing the percentage?

Dimmer dimmer_Pct_Ventilatie "Ventilatie [%d%%]" <fan> { knx="1.001:5/0/1+5/1/1, 5.001:5/3/1+<(5)5/4/1" }

5/0/1 is the control address for the 230V relay
5/1/1 is the status address for the 230V relay

5/3/1 pct absolute on 0-10V actor
5/4/1 pct feedback on 0-10V actor

You should post your relevant *.items entries to complete the "picture"
without this info and only with some sitemap entries it will be difficult for anyone to provide accurate help

Also: which AIO model? 0210 or 0410?

I believe that this is happening because you are not sending anything to the Switching actuator when you slide the dimmer item to 0%. The DPT 5.001 (percentage) is only linked to the AIO GA in your item entry.

Even if you were to deliver the 0% value to the Switching actuator… it wouldn’t accept it since it is not a dimmer (it only knows On/Off)

You are trying to “construct” an openHAB2 Dimmer out of 2 KNX endpoints. That sounds like spaghetti to me :slight_smile:

I would define 2 different items (one dimmer for the AIO and one switch for the AMI) and use rules to control their behavior.

By they way: What do you control on the ventilation unit with the AIO? (using the output voltage (0-10V)?)

The 0-10V is a control signal, I can change the intensity/power of my ventilation-unit through this. I live in Belgium and every newly built house is required to have some sort of ventilation (Ventilation D-system in my case).

end solution would be to increase air flow in my ventilation-unit when I’m taking a shower or we’re cooking (recirculating hood here).

Not so spaghetti-like btw…

HomeBridge-knx (a shim you can install on Homebridge to Homekit everything in your house) has two entries, one for brightness and one for ON/OFF.

Not so bizarre since brightness can be controlled by a completely different actor. There are for example EldoLED drivers for LED lighting which can be controlled by 0-10V and which you can switch off by cutting the 230V.

Not a popular opinion but that’s a defect in OpenHAB in my opinion :blush:

So… you want openHAB to transmit 2 KNX telegrams when you slide to 0% the dimmer item?
One with 0% value to the AIO and another with Off to the AMI?
You could easily do it with 2 items and a rule.
I don’t see any defect in OH :slight_smile:

Why give users the ability to define an ON/OFF address then with a dimmer? Sending 0% == OFF so: yes absolutely it should send two telegrams: the 0% and the OFF value, the defect (but also the flexibility I must admit) in OpenHAB lies in the fact that it doesn’t tie these two together itself where it should in my opinion. That’s why you have the ON/OFF in a dimmer…

So… let’s spam the KNX Bus because we want an easier config? :stuck_out_tongue:

I don’t think that you will find a lot of people in agreement with the above statement (certainly not me).

So… A 0% is not OFF in your world. Let’s make it a little bit more of a black and white story: Would like to see a lamp at 0% at your home and telling me it’s ON. :smile:

I don’t agree with your statement. I do understand it but don’t agree since on KNX brightness and an ON/OFF signal are two isolated things, as is the real world case I am presenting here… So OpenHAB (most certainly since you can define an ON/OFF channel together with a PCT value) should take this into account. Otherwise it shouldn’t support having an ON/OFF and you should define it in a seperate Switch item if we were to follow your way of thinking… The knife cuts both sides…

I wrote an answer but I deleted it…
good luck with your setup
My pasta is boiling and it’s time to eat :wink:

:smile: :smiley:

On a different note: there is some logic in your way too, imagine having one LED driver for 4 lighting lines and you dim one of them to 0% and the 230V to the driver shuts down --> all lights are off :wink:.

In fact, you could send OFF to your switch actuator if setting switchsupport in the sitemap, but I doubt this would help, I’m pretty sure the ON/OFF command would only be possible through Classic UI (without sliders) and openHAB won’t send an ON command if changing from 0 to !=0.

You want to use one item for two independent actuators, that’s not the way openHAB works.

I don’t know the MDT actuators, maybe it’s possible to get a 1-Bit-Info if the actuator is at 0, then you could use this as input to the switching GA.

If this is not possible, please use two items for two actuators and a simple rule to switch on and off:

Dimmer dimmer_Pct_Ventilatie "Ventilatie [%d%%]" <fan> { knx="5.001:5/3/1+<(5)5.001:5/4/1" }
Switch switch_Ventilatie "Ventilatie [%s]" <fan> { knx="5/0/1+5/1/1" }
rule "Auto switch Ventilatie"
    Item dimmer_Pct_Ventilatie changed
    if (dimmer_Pct_Ventilatie.state instanceof DecimalType) {
        if ((dimmer_Pct_Ventilatie.state as DecimalType) > 0 && switch_Ventilatie.state != ON) 
        else if ((dimmer_Pct_Ventilatie.state as DecimalType) == 0 && switch_Ventilatie.state != OFF) 

No need for more than one item in the sitemap, except if you want to see the state of your relay actuator …

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