Dimmer2 with Bypass2 spontaneously collaborated

[svossepoel 2]

Hi,

 

I have used a Dimmer 2 and Bypass 2 to dim a dimmable led light. The led light uses a very low load. The dimmer device measured 1 W (without own power consumption). 
All works fine: switching on and off, dimming. But after a short period (approx. 20 min) the dimmer starts a calibration cycle. After it light returns to original dimming level.  After a while, calibration cycle starts again. No notifications and nothing reported. 
 

Any suggestions what is happening here and how to fix it?

 

Thanks In advance for your expert advice. 
 

Sjaak

[Tim__ 112]

Check what parameter 35 is set to.  It could be set to recalibrate after a load error (If your bulbs are only 1W, the device  may think there is no load).  Try turning that setting off.

 

Let us know how you go!

[svossepoel 2]

Hi Tim,

 

Sorry for my late response. Holidays

I did check parameter 35, which was set to 1 for both devices (Auto-calibration performed after first power on). And I did notice it performed an auto-calibration after the first power on. I have now set it to 0.

But now the weird thing:

I have 2 Dimmer 2 devices, both with a Bypass 2, with having a similar load (same brand and type of bulb: LED with very low load). When I switch them on at night (whether that is done by the toggle switch or through the app doesn't make a difference in behavior), after some time (20 minutes or so) they both start what looks like an auto-calibration flow. But exactly at the same time. And it is not actually a calibration they perform, because the lights aren't switched off and on again. They first go bright is small steps to the max, then they dim again to almost off, and then they return to their original setting. After some time they do that again. And again exactly at the same time. At some point, they don't come back to the original brightness anymore, but stay very low. And yes, they are both on the same power source. No notifications, nothing.

Any idea what may cause this behavior?

[Tim__ 112]

I think the problem is that your load is too small. This is from the manual: supported dimmable light sources (power factor > 0.5) with minimal power of 5VA using FIBARO Bypass 2 (depending on the type of load).

If you try using a higher wattage bulb, I think the problem will go away.