PIR problem...

[Swicade]

...that's now doing my head in...

Basicaly i've got a set up where 2 external PIR sensors are turning on 2 outside 16w 2D lights. PIR's are wired in parallel so when either 1 is triggered it turns on both light fittings.

Whilst commisioning on walk test everything works fine and dandy.When lux level is turned to night and after timing out time is set to about 10 mins, i've then covered sensor one to bring on both lights...when timed out i've then covered sensor 2 turning both lights on and alls good.

The problem is now it's dark so system is in it's desired situation....once either sensor is triggered the lights come on but then stay on all night...

I've since wired the lights through a relay (sensors bring in a relay which then puts a supply onto the lights)...daylight tests all fine put just had a call saying the lights are still staying on at night without timing out.

Guessing possible faulty PIR but wondered if anyone else had been through the same and i'm missing something obvious.

Any suggestions appreciated

 

[ashrow]

Are the PIR wired on a perm feed ?
Some PIR's that are wired via a switch can be over ridden by switching the switch on and off and back on (or even if there is a power outage for a few seconds)
Other then that disconnect one pir for a while to see if one is faulty (just takes a few more visits to fix)

 

[nick611]

i have done paralell pir.s and never had a problem. i know this dosn,t help you. try one at a time for a night .its a pain but it will prove each pir. i can,t think of a reason why this set up would,nt work

 

[HandySparks]

Try backing off the times on both PIRs to, say, a minute. Some PIRs tend to latch on when set towards the higher end of the time range, particularly the cheaper ones.

 

[telectrix]

agree with above. sounds like a PIR is sticking on. some PIRs have been known to randomly trigger on inductive loads, but that's not what you've got by the looks of things.

 

[tazz]

Sounds like the pirs are to close to light fittings...when lights turn on the pir(s) are sensing heat, hence all tests are working fine

 

[needasparks]

Could it be not enough resistive load for the PIR's, I've never tried only 16watts of inductive on them.

 

[telectrix]

if the PIRs thought it was day, they'd turn off .

 

[needasparks]

Thats why i discounted that part as a red herring

 

[tazz]

yes just edited to say heat, blonde moment

 

[Swicade]

The alteration of set time sounds a good starter for me to try tbh.

Hadn't even considered the lack of resistive load...though i'll admit i'm alittle confused as to why that would effect the PIR switching off again which kinda brings me back to the latching problem mentioned by Handysparks and Telectrix.

Perminant non switched live feed to the system and whilst i can see the issue of heat from lamps (especially if halogens fitted) 2d lamps tend not to give off much heat when working (i will be double checking this though)

Thanks all for the feedback....thought i was going mad and started to question meself on wether i'd wired up wrong somehow (always good to question yeself at times anyway)

 

[tazz]

Apollogies Swicade, comment to quick without thinking

 

[Swicade]

No need to apologise, you can call me anything you want....just dont call me surely!

tbh no idea what your apologising for anyway...think i missed something so we'll agree it never happened :wink_smile:

 

[alarm man]

what pirs are they,is it a system or something youve done yourself,external pirs will become more sensitive at night when its colder,is there any heating flues adj the pirs,it could be tripping every couple of minutes but if its set to 10 mins and the pir is always tripping that maybe why the lights remain on.

 

[Guitarist]

Does this happen on your daylight tests if the photocells are covered on both units, to simulate darkness?

 

[Swicade]

The problem only occurs at night,when tested during the day everything works fine.

No heat sources (still waiting for the plu...erm water guy..to connect up the boiler) and sensor's well away from any flue's when boiler is finaly connected. It's at an empty bungalow thats being done up with the client going there at night painting etc hence the calls telling me they wont reset.

they're stand alone sensors from wholesalers (Friedland L220NBLK 200deg (just found delivery ticket in me pocket))....definitely leaning towards the latching problem, blowing my brains abit the fact it's only a problem at night and not in the day.

 

[alarm man]

The problem only occurs at night,when tested during the day everything works fine.

No heat sources (still waiting for the plu...erm water guy..to connect up the boiler) and sensor's well away from any flue's when boiler is finaly connected. It's at an empty bungalow thats being done up with the client going there at night painting etc hence the calls telling me they wont reset.

they're stand alone sensors from wholesalers (Friedland L220NBLK 200deg (just found delivery ticket in me pocket))....definitely leaning towards the latching problem, blowing my brains abit the fact it's only a problem at night and not in the day.

that maybe the problem,cheap pirs,they wont trip thru day due to photocell but at night they will pick up anything,heat from next doors flue moving trees/bushes etc

 

[jimmymac]

How long has this been occurring?

Reason i ask is some PIR's have a over-ride function where they will operate as a normal floodlight for 6 -8 hours. You usually activate this function by switcing them off - on - off - on within a couple of seconds............just a thought

 

[Guitarist]

The problem only occurs at night,when tested during the day everything works fine.

No heat sources (still waiting for the plu...erm water guy..to connect up the boiler) and sensor's well away from any flue's when boiler is finaly connected. It's at an empty bungalow thats being done up with the client going there at night painting etc hence the calls telling me they wont reset.

they're stand alone sensors from wholesalers (Friedland L220NBLK 200deg (just found delivery ticket in me pocket))....definitely leaning towards the latching problem, blowing my brains abit the fact it's only a problem at night and not in the day.

That's why I asked if you had tried covering BOTH photocells together and not one at a time, as this would simulate darkness.

 

[Swicade]

Admittedly i haven't covered both cells at the same time...i'll try that tommorrow in daylight (or more like dull daylight the way the weather is) and see what happens.

Could be the cheap £15 PIR's....out of interest any suggestions on quality brands of stand alone PIR's?