[SOLVED] How to send status telegrams to KNX?


in parallel to the OH UI I would like to use a KNX taster to switch the item as well. Everything works fine but I don’t get a status update on the KNX taster if I switch the item from the OH UI! So, without a KNX actor nobody sends a status telegram to the KNX taster. Maybe I missed something but how can I generate a status telegram out of OH to sync the taster status with my UI?


You need two knx adresses for this on your knx-switch, one for switching and another one for status.

I only have knx actors, so they gave me this two adresses.

Can you show me your items-file with the knx adresses you gave to the switch?

I think you have to set the same knx adress to both fields in your knx switch.

additionally to Halloweens comment: Do you have the KNX touch sensor / switch actuator configured in the ETS with a status GA?

So, here’s from the documentation http://docs.openhab.org/addons/bindings/knx1/readme.html#items-configuration

Dimmer TestDimmer "TestDimmer [%s]" (Lights) { knx="1/3/20+0/3/20, 1/3/21, 1/3/22+0/3/22+0/8/15" }

so, while this is Dimmer-item, it explains:

  • 1/3/20: Main GA (in your case, the GA for switch ON/OFF
  • 0/3/20: listening GA (in your case the Status GA - mostly used for the LED on touch sensors)

the rest is dimmer specific:

  • 1/3/22: set percentage GA for the dimmer
  • 0/3/22 and 0/8/16: listening GAs for the percentage status
  • 1/3/21: Increase and Decrease GA for the dimmer

You´’ll need your equivalent for 1/3/20 and 0/3/20 and if it’s a switch-only item:

Switch TestDimmer "TestDimmer" (Lights) { knx="1/3/20+0/3/20" }

you’ll get two things out of this:

  • if you switch via OH2 UI, the status will change in the touch sensor as well
  • if you switch via the touch sensor, the OH2 UI will change as well

Yes, I have two GA:

0/1/25 for switching
0/1/26 for status

Note, there is no actor behind. Only my MDT taster is connected with these GA one with the switch command and the other with the status. I want to switch a scene (a switch item) via the taster which then is triggering a rule for switching several items.

My item configuration:

Switch SceneDinner		""					{knx="0/1/25+0/1/26"}

I can switch the scene from the taster but I don’t get a status back from the OH in order to turn the status of the taster into ON.

I think this doesn´t work this way, openhab has no status-address like knx. The status can be seen in the switch-item. So i think you have to write the same GA 0/1/25 into your MDT Sensor into “Schalten” and into “Rückmeldung Schalten” (i don´t know the exact description for this).

Without an actuator you have to build a rule in openHAB to send the status GA telegrams.
Note: you can only send one GA from an knx touch sensor. Normally the actuator sends a status GA then after switching/dimming/whatever.

So, your MDT sends 0/1/25 and you have to bring 0/1/26 in line: You need to

  1. Add another item in OH2 and
  2. Change it in line with your switch.

I’m on my mobile, if you need help please tell and I’ll do my best to type it in :stuck_out_tongue_winking_eye: - otherwise please post the result, as it would be of help for others… Thanks!

This isn’t a “real” knx solution…:wink: It has unwanted side effects, if you add an actuator later. Please don’t do this…

Do you want the status to get the led of the MDT switch blinking?

If it is only for this case, maybe you can switch the led on/off with an external knx adress? So you can make a rule to switch the led when the scene is “on”?

Thanks this works!

If have added a second item

Switch SceneDinner		""									{knx="0/1/25"}
Switch SceneDinnerStatus	""									{knx="0/1/26"}

and I switch SzeneDinnerStatus via a rule as you proposed.

rule SwitchSceneDinner
	Item SceneDinner received command
	if (receivedCommand == ON) 
	     sendCommand(SceneDinnerStatus, ON)
             sendCommand(SceneDinnerStatus, OFF)

It works, the LED of my knx MDT taster turns on or off.

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In my installation the GA for status and switch are the same

This was realized by a electro-company.
Is this a wrong way?

It is problematic for automation, yes.
normally the status GA are set to different GAs as the actuators’ GAs. That way the visualisation (and openHAB!) have more flexibility to use the different GAs as intended. In a simple “only switch sensors” it’s not neccessary (read: makes live a bit more complicated for the electrician…).
So, If you have Access to your ETS you could easily change that.