KNX - Dimmer with 3W light


I know this isn’t the correct place for this question but this is one guy on here that is genius at this stuff so i’m going to try my luck.

I have 3W dimmable light which is connected to my TheBen dimming actuator, whenever this light turns on it is set to turn on from 1% - 100% over 4 seconds which works on every other light I plug in.

However, with this 3W light there is almost a little spike in the voltage that causes it to turn on at approximately 20% then dim down to 1% then dim all the way back up to 100%.

It makes for a pretty gross abrupt switch on.

Any help would be greatly appreciated.

I have a couple of lights that do something similar. In my case they are actually non-dimmable lights. Have you double checked that your 3W light is in fact dimmable?

Yeah man, specifically got them because it said it was dimmable - has a dimming driver on it.

It Dim’s down beautifully, and dims in between values perfectly. It just that initial ‘on’ that abrupt

Thank you for even replying, been banging my head against this for hours.

I don’t have a Theben KNX dimmer, I have MDT ones myself.
Mine have different modes or dimming curves that can be set depending on the type of light that are connected to them. I’m assuming the Theben would have something similar.
Have you tried playing around with those?

Honestly, can play around with load selection but that is it. I don’t seem to have the dimming curves you’re talking about? Is it something I will need to add?

Could I be using the wrong group object for a light this size?

Its frustrating because the other lights dim so perfectly.

I figured it out! Well not exactly figured out why it happens but resolved it.

The light needs to receive an immediate on command from the actuator when it tries to dim it seems the driver is trying to do its own dimming and the actuator trying to force it to dim another way.

So when I switched the receiving switch order to ‘immediate on’ it works perfectly. No more janky on off.

I hope this helps someone in the future.

1 Like

Mark your solutions as solved and maybe clarify the title a bit. This will help people find the issue easier in the future.

how do I mark it as solved?

I’ve contacted an admin to help out.

To have the ability to mark a topic as solved you need to post it in a forum category. I have moved this topic to the Configuration category. You should now be able to mark the post that helped as the solution.