PIR Setup/Sensitivity

I'm having some issues setting up a few 5753L Sensors at a few different customer sites and i'm hoping someone out there will be able to assist me.

What is the best way to go about setting the pot for the lux sensitivity?

There are a few locations where i have set it full positive and full negative and the sensor always triggers "Motion in Darkness"

 

My method so far is to set the group address to come on for 1 second, and select ML and MD. Then turn the pot completely clockwise then slowly turn it back until the light triggers, then adjust slightly for the current light level.

I have multiple sites where the PIR keeps triggering in a adequately lit hallway even though the pot is set fully clockwise. Then i have other sites where it needs to be pitch-black before it triggers.

 

If you are using the 5753L, the recessed 360 degree sensor... I find that it varies responsiveness at different degrees, thus rotating the sensor can make it more or less responsive.

I'm not sure if this is technically accurate, but I've certainly experienced this result. Possibly its rotating the beams so that they are broken more effectively at that position.

 

This is exactly the result you can expect, especially when installed in low ceilings. If you look at the detection pattern on page 4 in the Installation Instructions you will see these detection "fingers" radiating away from the sensor. It's when you cross the boundaries between the sensing fields of view that the sensor will pick you up. Tweaking the rotation of the sensor to achieve the best performance is definitely the right thing to do.

If you want to optimise the detection lengthways down a corridor, for example, you can get a bit extra sensitivity by aligning the boundary between adjacent sensing windows on the lens with the long axis of the corridor.

 

Is that pattern the same on every sensor? ie: can we install it the way we want the first time?

 

Yes, the pattern is exactly the same on every sensor. The rotation of the lens is keyed to the housing.