Dual tech' PIRs - Good/Bad ?

[Alarm]

So to set my mind right, your working on anothers graded system with not a clue how the detectors work?

 

[oasistechnical]

when you speak to the installer engineer, ask him to check the mains incoming to ground, just to see if there are any mains borne faults,

also get him to fit a low pass filter on the incomming supply and the 12v out to devices, some panel (not all) do not have the smoothing capacity of others, so mains interference will cause false alarms.

11v at the pir, = not good!!!

get them to do a FULL check of all ac and dc supplies.

Oasis

having been at this job for a few years we still come across mains interference and we always carry on the van, filters for mains and dc supplies.

we have just completed a motor repair shop local to us, and one of the first things we noticed that when the 3 phase compressor kicks in the fluorecents dim slightly, upon putting a nifty bit of kit on the supply for a couple of days we noticed a significant rise and fall on the supply,

so this particular site now has a small UPS in a secure (graded) enclosure to supply filterd supply to the panel. a bit costly but the system now works fine, with no problems,

all it takes is abit of know how and a bit of time (but as we all know clients want it working NOW not later)

hope this helps your problem.

Oasis (again)

 

[alumni]

Thanks Oasis. That answers my question. Now I wonder why there have been problems. The engineer did mention low voltage to the sensor. 11v when the battery was showing 13.3,
Is it possible if the local mains electric has spikes and drops (I have noticed occasional unexplained 'dipping' of the lighting.Not totally out but just occasional dimming for perhaps half a second.)

I don't know exactly what the alarm company have done when upgrading what was an existing system. It used to be part of one building now the bit we have has been segregated from the original building with all new services installed ie gas and electric.However the original alarm wiring was reused and adapted where necessary.
This is obviously my first experience of dual tech sensors and the alarm companys solution to the alarm being seemingly activated by vehicles parking outside the building was to turn down the range of the microwave output in every sensor to 25%(apparently the lowest it can be set).

The battery will, if everything working correctly, show greater than +13v.

11v at the detector is not really ideal, but not necessarily the cause of the problem. Remember in many commercial installs the cable runs may be significantly longer than your average semi det., hence showing greater volts drop. Remember, you get a somewhat similar effect on battery powered units as they run out of puff.
That said, the engineer would/should know if the detector voltage has changed from install.

Having now mentioned the wiring is from existing install, rather than look at the sensor, i'd be more inclined to be looking at the integrity of the wiring rather than blame a detector. Dodgy joints can be affected by a number of things, not least temperature changes.

 

[oasistechnical]

the more connections you have on a bit of cable to more resistance you have.

that why on older installs that we adopt, we check every bit of cable, and if it dont come up correct it gets re wired!

Oasis

 

[alumni]

when you speak to the installer engineer, ask him to check the mains incoming to ground, just to see if there are any mains borne faults,

also get him to fit a low pass filter on the incomming supply and the 12v out to devices, some panel (not all) do not have the smoothing capacity of others, so mains interference will cause false alarms.

11v at the pir, = not good!!!

get them to do a FULL check of all ac and dc supplies.

Oasis

having been at this job for a few years we still come across mains interference and we always carry on the van, filters for mains and dc supplies.

we have just completed a motor repair shop local to us, and one of the first things we noticed that when the 3 phase compressor kicks in the fluorecents dim slightly, upon putting a nifty bit of kit on the supply for a couple of days we noticed a significant rise and fall on the supply,

so this particular site now has a small UPS in a secure (graded) enclosure to supply filterd supply to the panel. a bit costly but the system now works fine, with no problems,

all it takes is abit of know how and a bit of time (but as we all know clients want it working NOW not later)

hope this helps your problem.

Oasis (again)

Agreed.
It's surprising just how many dodgy supplies there are out there.

Earth loop faults are usually high on the list of suspects when A/C and CCTV problems arise.

 

[AdrianMealing]

And there is still something missing from this thread, if it is a grade 3 system, then the DualTechs (whatever they are) will have to have Anti Masking, this could also be the cause of the false activations., as i have already said, without confirmation of which sensors are installed we are clutching at straws.

I don't disagree with anything Oasis and Alumni have said, but just thought i would throw this into the pot.

 

[Alarm]

yep that's right I do not know - that is why I am asking questions but as is the case with so many people asking questions on this forum trolls come along to insult and disparage.

Thanks to Mr mealing I am getting some answers so I can try and understand why there has been problems.

If I don't know the difference betwwen 4 core and 6 core wiring and std and dualtech then I will ask and am willing to be educated.

In that case look up sequential quad Pir.
That will give you a clue on your misguided assumption on a Dual tech.

As above, a name for the detectors will enable a precise answer rather than an all encompassing one.

I still wonder why your getting involved in anothers maintained system?

 

[yaleguy3]

Thanks everyone and I mean EVERYONE for your assistance in this thread.
I know we have locked horns many times but this thread is definately a refreshing change.
I think we are definately getting somewhere near.

Adrian you mentioned anti masking and that was suggested as a probable cause though I don't know why as the environment is extremely clean no dust haze or anything that could cover a sensor. It is grade three but the engineer mentioned they could turn the anti masking off.
Whenever they make suggestions that to me reduce the effectiveness of the system or take away a feature I see as useful I always ask them whether it would affect the alarms G3 status.
Would hate for the insurers to have a get out of jail card so easily.

 

[alumni]

Adrian you mentioned anti masking and that was suggested as a probable cause though I don't know why as the environment is extremely clean no dust haze or anything that could cover a sensor. It is grade three but the engineer mentioned they could turn the anti masking off.

Because chasing possible cable faults ain't always the easiest option.

 

[bernardgreen]

The engineer did mention low voltage to the sensor. 11v when the battery was showing 13.3,

Possibly the 13 volt from battery feeds a voltage regulator that feeds the sensors. A good design would have such a regulator to protect the sensors from over voltage when there was fault in the battery and it charging system.