Light detection of a motion detector VMBPIRM



I have a problem with a motion detector (VMBPIRM).
It is on the ceiling in a room without door but with closed curtains… so it is rather dark.
And the light detection says it is between 25 and 30… then it does not detect properly the luminosity.
The detector in the room next door says that the luminosity is around 600.

Do you know what can be the reason?

Thank you


Does it stay at the same value if you open the curtains, or if you shield it completely from the light?

If possible, try to power cycle the module (or the complete installation).

You can also try a firmware upgrade and see if that fixes the problem.


I checked again now.
The value with curtains open (day light) is 100.
The value with curtains open and light on is 39.
The value with curtains closed (very dark) is 300.

I guess this would be a normal behaviour if there was a multiplication factor of 3 or so…

I cannot do a firmware update. This is already the latest build (1817).

Can you please tell me how to do a power cycle or a complete installation?

Thank you


By “power cycle” I simply mean to disconnect the power briefly (a few seconds), then reconnect it. If it’s too difficult to do this for the module itself, you can simply switch off the current for the whole installation (eg. disconnect the 15V + wire briefly).

You could first try right-clicking on the module in VelbusLink and selecting “restart”, which is like a soft restart, see if that changes anything.


I don’t have “restart” in the popup menu when I richt-click on the module.

However, we disconnected the whole installation yesterday (for an independant problem). And now I see that it’s night and the value indicated is the maximum (1022)… so, correct behaviour.
I’ll have another look tomorrow with day light.


Yes, sorry, you have to go in Advanced mode (under Tools) first, forgot to mention that.



Sorry to come back only now on this. I first completed other parts of the configuration and I am now again looking at the configuration of the motion detectors.

At the moment, almost all my VMBPIRM have a strange light detection, which gives problem for light dependant motion detection.
The lights turn on all day long… even where there is enough light.

For the modules inside a closed room without light, it’s 1023… the maximum. That’s fine.
But for other rooms where there is light, the value is between 0 and 20 or maybe 30 when it becomes darker.
The sacle is obviously not linear. But it seems there is no value between 30 and 1023…

I have another problem of another module which detects a light value of 635 (it is inside, on the ceiling, in front on the entrance door). When I open the entrance door, the room becomes lighter… the value goes to 637… the opposite behaviour than expected.
This is very problematic as basically the light dependent motion detection also does not work there.

The VMBPIRC’s I have in the house seem to detect the light correctly.

I have restarted the modules, upgraded the firmwware (which was in any case already the last version).
I have not seen a configuration which could be linked to this.
Might it be an installation problem?

Are the VMBPIRM known for light detection problem?
Should they be replaced? (guarantee)

Thank you


Could you please send your .vlp to (with a reference to this topic), maybe we can see something there…