Intermittent PIR Issue

Hi,

I'm recently started to have an issue with all 3 5751L PIR's that I have in my house.

The PIR's all successfully turn on the group after detecting movement. However all 3 are now intermittently (1 in every 10 times) not turning the group off when the timer expires. This only appears to have occured since I upgraded to the CBus Toolkit.

Any ideas what could cause this?

All other CBus devices are still working fine. Configuration of the PIR's has not changed.

Thanks,
Rob.

 

The only thing that could make this happen is if the network has become slightly unreliable. Try going through all your output and system units on your network and make sure you've only got 1 burden enabled and no more than 3 units have the clock generator enabled.

 

I've checked that both the burden and clock settings are correct, and I'm still experiencing this problem. Everything else on the CBus is working perfectly.

Any other suggestions that I could look at?

Thanks.

 

I'd still suspect a network quality issue. I suspect this because all 3 PIRs are being equally affected.

You don't have access to a CRO to check the waveform do you? Also, check that you don't have a hardware burden plugged in somewhere, giving you 2 network burdens (hw + sw).

It would be interesting to set the units up on an independent sub-network to check their reliability. Technical Training and Support should be able to talk you through any issues you're having.

 

the answer may be blowing in the wind

Just another thought (and I have seen this before) make sure that the PIR's are not being retriggered by some other heat/movement source (draughts or pressure differences between the room and the roof space that the PIR is wired through into etc), To confirm if there is something re-triggering the unit(s) place a cardboard cover across the sensor lens (hold it there with sticky tape etc) and confirm that the load always turns off as programmed. Check if the miss behavior only or mostly happens on wind/hot days etc or when cirtain doors/windows are open etc.