KNX dimmer - detect listening adresses

Hi all,

Yesterday I finally managed to connect knx to openhab and control the switches. However, I also want to dim the lights.

The light switches in my house are switches that turn on with one push, and if you hold the button for a longer time (up or down) , the light gets brighter or is dimming.

Now I already looked into dimmable items and how to configure them, but I cannot detect/find my listening addresses. We recently bought the house so I also have no ETS configuration file.

How can I find these listening addresses?


You could try the following: Use the knxtools (e.g. vbusmonitor) and monitor the telegram traffic when you perform the dimming action using the physical switch.

I have never done this but in theory it should be possible to identify the GAs like this. It may take some trial and error until you get this right :slight_smile:

there is a commercial solution also: (I don’t have experience with it)

Well, the first thing is… the ETS configuration file is part of documentation, and there is no option not to get this file if getting a knx installation (yes, I know, theory and practice…).

To get the needed information, you have to set knx logging to debug. After that, just press the buttons (short and long) to get the Group Addresses; you will see them in the log of openHAB. At least there are two different GA for Switching ON/OFF and dimming UP/DOWN, but you would like to have

GA 1:ON/OFF (sent from wall switch to actuator)
GA 2:ON/OFF (sent from actuator to publish state)
GA 3:INCREASE/DECREASE (sent from wall switch to actuator)
GA 4:Percentage (sent from openHAB to actuator)
GA 5:Percentage (sent from actuator to publish state)

In most installations, GA 4 and 5 are not set, so you would have to use GA 3 from openHAB side to set the level of the dimmer.
But there is possibly another issue, openHAB does not support START/STOP dimming, and this is the most common way to use knx dimming with wall switches.
So, be prepared not to be able to do dimming with openHAB, until you are able to reprogram your knx installation.

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Yeah indeed I have found the start stop dimming address. I’m afraid the lights are configured by start stop dimming.

Is it easy to reprogram an individual switch via ETS? Or do I than have to reconfigure the entire KNX setup? I haven’t used ETS before…


The biggest part is, to get all information. ETS is able to read some sort of data from actuators, sensors and wall switches, but there are some parts that can’t be restored (it depends on what kind of hardware you are using).

Ok Thx. The interesting thing is that with the 3.008 bit configuration in ETS I can dim the light. Can I also configure this in openhab2?

No, the DPT is 3.007 (in fact, as the main DPT is 3, this is a 4-Bit-Nibble, MSB is UP/DOWN respectively INCREASE/DECREASE and the 3 LSB are the step width. A %x000 would be “STOP”, but openHAB does not use this command.)

At the moment, there is no easy way to send a %0000 or %1000 from within openHAB.


I noticed that none of my KNX items actually show up in my log when I turn a switch manually.
How can I fix this? I already have strange configurations, but this was the only way I got it working…

I described my knx switch items like this:
Switch TestItem “Switch 1” {knx=“1.001:7/0/0”}

My other bindings (like Toon) do work and appear in the log.


Solved it, in config file --> ignorelocalevents = false