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A Strange Pir Problem


Alarm boy

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Posted

Hi,

Just a quick question...

Is the PIR wired using common wiring? i.e. + & - and one zone wire?

(This was often used in the old days, to save on wiring)

Similar problems can also be encountered using keypad zones.

What happens is that when the one PIR triggers, it effects the voltage on the other. Because this is connected to the zone, it can effect the zones resistance (V=IxR), causing the 2nd PIR to go into alarm.

Probably not the case...

n

Posted
Hi,

Just a quick question...

Is the PIR wired using common wiring? i.e. + & - and one zone wire?

(This was often used in the old days, to save on wiring)

Similar problems can also be encountered using keypad zones.

What happens is that when the one PIR triggers, it effects the voltage on the other. Because this is connected to the zone, it can effect the zones resistance (V=IxR), causing the 2nd PIR to go into alarm.

Probably not the case...

n

Good point. Did Alarm Boy mask off the hall detector during the process of elimation steps to ensure it was the not the hall PIR influencing the kitchen PIR before looking for the reflections, etc?

There's no substitute for experience .......... so all opinions welcome!

Posted
Good point. Did Alarm Boy mask off the hall detector during the process of elimation steps to ensure it was the not the hall PIR influencing the kitchen PIR before looking for the reflections, etc?

Run that past me again?

How can one PIR influence another PIR?

Posted
Run that past me again?

How can one PIR influence another PIR?

I think (though I shouldn't assume) that he means that the hall pir is triggering thus drawing more load which in turn is causing a voltage drop to the pir in the kitchen causing it to trigger.

I can't think of a better explanation (apart from reflection as mentioned earlier) but I think it's highly unlikely given the tiny ammount of current that the average pir uses.

First thing I would do is mask the kitchen pir, if it cures the problem then it's got to be reflection.

Bear in mind most solid objects don't allow infra red to penetrate or at least not in the frequency range that pirs are sensitive to, on this basis solid objects must either absorb or reflect the ir.

Posted
Run that past me again?

How can one PIR influence another PIR?

He's talking about an unconventional way of wiring PIR's .... At each pir fit a link from + to C, then connect zone wire to NC. This would mean that the common + wire is supplying 12v to several PIR's and the + to each positive alarm terminal, thus when one PIR goes into alarm there is a possibility of a volts drop to the positive alarm terminal in other PIR's.

Clear as mud?

.

.

.

PM me for access to the SSAIB members discussion area.

Posted
Hi,

Just a quick question...

Is the PIR wired using common wiring? i.e. + & - and one zone wire?

(This was often used in the old days, to save on wiring)

Similar problems can also be encountered using keypad zones.

What happens is that when the one PIR triggers, it effects the voltage on the other. Because this is connected to the zone, it can effect the zones resistance (V=IxR), causing the 2nd PIR to go into alarm.

Probably not the case...

n

So why is it ok with the door shut?

The opinions I express are mine and are usually correct!

(Except when I'm wrong)(which I'm not)

Posted
Dont remember seeing a rodent detector although will check on next visit. but as i say i have stood still away from the detector and its fine (no LED indication at all) as soon as you slightly move in the hall behind it the LED comes on every time! yes i did just change the PCB in the detector. Are you saying i should slightly relocate the detector?

even pyronix dont know.

Im starting to belive the saying "iv got eyes in the back of my head"

cheers for the replys

Yes, either move back plate to see if picking up reflected IR, or re-site detector within same room. As you have swapped for a known good detector (& presume no probs with where you swapped from) so better to use proven than get new unproven if you see what i mean.

Cost = nil also :)

Posted
So why is it ok with the door shut?

I did not recall reading that it was ok with the door shut? But you seem to be an expert, so I will bow to your superior knowledge, and the fact that you may be more literate than me. Your tag line clearly states that you are more knowledgeable than me..."The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not)" I just wish I knew as much as you do. And I just hope that when I do, I am able to stay humble....

All I asked was, was it wired right? I had a similar problem once, and this was the problem.

I was just trying to help. I have learn't that I don't know everything, and that I can learn every day, sometimes from surprising sources....

Sorry, for my suggestion. I retract it. Perhaps you can assist in solving the problem, as opposed to just critising suggestions?

NN

NN

Posted
I did not recall reading that it was ok with the door shut? But you seem to be an expert, so I will bow to your superior knowledge, and the fact that you may be more literate than me. Your tag line clearly states that you are more knowledgeable than me..."The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not)" I just wish I knew as much as you do. And I just hope that when I do, I am able to stay humble....

All I asked was, was it wired right? I had a similar problem once, and this was the problem.

I was just trying to help. I have learn't that I don't know everything, and that I can learn every day, sometimes from surprising sources....

Sorry, for my suggestion. I retract it. Perhaps you can assist in solving the problem, as opposed to just critising suggestions?

NN

NN

Sorry if you took offence and threw your toys out of your pram, It wasn't a personal criticism of you, just an observation.

Had a bad day???

The opinions I express are mine and are usually correct!

(Except when I'm wrong)(which I'm not)

Posted
Sorry if you took offence and threw your toys out of your pram, It wasn't a personal criticism of you, just an observation.

Had a bad day???

now now children

Ryan Williams - South coast service engineer for Banham Fire & Security Group*

*Comments are my own and do not reflect those of Banham Fire & Security Group.

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