Depiction of a KNX impulse switch

Hi there,

I’m a bit lost where to put this (probably stupidly simple) question, so please move it if needed.

Basically I’m using KNX to operate the garage door, simulating a manual impulse switch that is usually installed in the garage. The KNX taster is configured to send the “on” command to the group address, and the actuator is configured as an impulse switch to short the wires of the garage door contact.

The actuator only has a “write” address where the “on” command is sent; it doesn’t have any “read” address to report the status. The actuator closes the switch only for half a second, then goes back to “off” state.

What I don’t know is how to depict this in OpenHAB. Currently this group address is bound to a “Switch” object, so it gets the “on” messages on the bus but doesn’t know that after half a second the status needs to go back to “off” state. There is no telegram configurable to announce the “off” state, nor a group address with the status. So OpenHAB either shows an unknown state (after a restart when it has not received any garage opening command and cannot query the current state anywhere), or is perpetually “on” which is false.

How can I fix this, please?

Many thanks in advance!

If you could manage to get an “off” reply from the actuator - that would be the best solution.
I have a similar case, added a rule to automatically switch off after [ x ] ms.

ECMAScript 2022+
Trigger: When < item > changed to ON

setTimeout(() => {
  console.log("Kompressor", "Autom. nach 5 Min. aus");
}, 5*60*1000);

See also

Thanks for the quick reply, Jens!

Unfortunately, the actuator doesn’t reply with any status update when it switches back off. I looked through 4 different actuator models which advertise “extensive impulse and staircase light features”, and the moment I configure the actuator channel as impulse switch, the status disappears.

I could set it up as a normal toggle switch (to preserve the status function) then add a script in OH to switch it back off after a while, but that would defy the purpose of KNX being completely independent and fully functional.

If there is no object type defined in OH for impulse switch or temporary button press, then I’ll just use a script to reset the status in OH.

Thanks again!

Another solution:

Item looks like this afterwards

Awesome, this is even more straightforward!! Implemented, now I have to wait to test it :slight_smile:

An even simpler solution is to set metadata autoupdate to false. This is: openHAB shall not set the status of this Item to a state when a command was issued.
And use a simple button instead of a switch, of course :wink: