PIR Continuity

[Brian246]

I bought a PIR for an installation the other day and I was intending to use it for a contact but as soon as power is applied the live and switched live have continuity whether the PIR is triggered or not, I’ve tested a couple of different PIRs already installed and this doesn’t seem to be the usual case. The PIR works fine if wired into a light fitting but I’m after using it for a contact. I’m just wondering if I could ‘adapt’ it to suit or whether I should just try another PIR?

thanks in advance for the help.

 

[Leesparkykent]

I bought a PIR for an installation the other day and I was intending to use it for a contact but as soon as power is applied the live and switched live have continuity whether the PIR is triggered or not, I’ve tested a couple of different PIRs already installed and this doesn’t seem to be the usual case. The PIR works fine if wired into a light fitting but I’m after using it for a contact. I’m just wondering if I could ‘adapt’ it to suit or whether I should just try another PIR?

thanks in advance for the help.

It’s common for a PIR to close for a few seconds when power is applied....for example when the MCB is turned back on or after a power cut. What are you using the PIR for?

 

[Brian246]

The PIR constantly has continuity even if it’s been on for ages. Whether the PIR is triggered or not there is continuity between the two contacts. I’m using the PIR to trigger a relay.

 

[westward10]

So is the relay constantly energised.

 

[Brian246]

Yes, there is constant continuity but not voltage until the PIR is triggered.

 

[westward10]

So you have 230v at the relay coil terminals which is energizing it permanently.

 

[Lister1987]

This may or may not help;

Motion sensor wiring with switched override feature

Two wiring diagrams for outside lights controlled by PIR motion sensor with a switched override feature to allow the lights to be permanently on

www.flameport.com

Just to sanity check wiring

 

[radiohead]

Swap it for one of the PIR's already installed if they are testing OK for your purpose and the one you have operates normally with a light.

 

[Brian246]

So you have 230v at the relay coil terminals which is energizing it permanently.

Yeah, it’s never not triggered regardless of whether the PIR is triggered or not.
[automerge]1583909065[/automerge]

This may or may not help;

Motion sensor wiring with switched override feature

Two wiring diagrams for outside lights controlled by PIR motion sensor with a switched override feature to allow the lights to be permanently on

www.flameport.com

Just to sanity check wiring

I thought that originally but I’m 100% sure it’s as I thought now

 

[Brian246]

Swap it for one of the PIR's already installed if they are testing OK for your purpose and the one you have operates normally with a light.

I can’t, this one needs to be one for an internal angle and the customer is very specific on atheistic. I think I’ll just have to get another brand and hope for the best.

 

[telectrix]

some PIRs don'tlike inductive loads (relay coil). try a 0.1 mfd capacitor (300V, non-electrolytic) across Lout and N.

 

[littlespark]

Put a lamp in the circuit with the coil

 

[Brian246]

Put a lamp in the circuit with the coil

some PIRs don'tlike inductive loads (relay coil). try a 0.1 mfd capacitor (300V, non-electrolytic) across Lout and N.

but even if there’s nothing on the load side of the PIR there’s still continuity

 

[davesparks]

Your PIR probably has an electronically controlled output rather than a relay output.