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Pir Choice


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Hello,

I'm just in the process of selecting some suitable PIR's for our install.

I've been reading up and will probably be looking at the texecom range.

I understand the idea being Dual Tec's - but not so sure about the QUADs.

As I understand, the Dual Tec's use both microwave and PIR to detect movement - should one of the two trigger, no alarm will sound - should both detect then alarm will sound.

However, could someone provide a summary of QUADs and when/why they would be installed over standard PIRs?

The Texecom Prestige Quad is only a few quid more than the bog standard Prestige Compact IR but the Dual's are almost double.

Also, these mirrored optics - more expensive than the QUADs but cheaper than the Dualtecs - what's the benefit of them?

Thanks!

Alex

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P.S. I understand that both the 4 "box" sextions need to be activated before the alarm sounds but texecom advertise this for "harsh" env. yet some forum threads here use it as standard?

I don't quite understand that! :)

i use quads as standard, less chance of false alarms. Not that much to think about, you have the right idea.

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Hi, Basically all movement detectors work on the same principle-they see movement of some description.

PIR's Should theoretically see heat movement or a change in heat distribution-but all PIR's are not equal.

Cheaper PIR's can react to certain movements that should be regarded as inoffensive-such as a curtain moving or a piece of paper dropping off a notice board-the better devices will discriminate between the two and provide more security against false alarms.

At the higher end as you have said combined infra red/microwave will meet the criteria but are more expensive.

A cheap PIR may well just send a beam out at and look for movement-a quad sends numerous beams out looking for movement and ascertaining wheather that movement should be regarded as a intruder situation.

This is a classic example of why the regs are being implemented/updated-The aim especially with monitored or policed systems is to reduce false alarms-and thus unwarranted police response whilst they could be at a more serious crime scene.

Obviously the better a detector is at doing it's job the more people will trust it for what it's supposed to do!!.

But the same applies for the domestic bells only system as well-you want to know that if it's gone off-It's gone off for a legitamate reason!.

Richard.

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A cheap PIR may well just send a beam out at and look for movement-a quad sends numerous beams out looking for movement and ascertaining wheather that movement should be regarded as a intruder situation.

WTF? :hmm:passive infra red

De Do Do Do, De Da Da Da. De Do Do Do, De Da Da Da

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i use quads as standard as well :)

Kevin Scott. Owner of KK Alarms...... Installation .. Service .. Repair ...... Thoughout.. Northumberland and North Tyneside ..... Tel:01670 361948 (call diverted after 15 seconds) or 07947444114

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thanks for the replies - i'll buy them 4 beam ones ;) hehe

so quads minimum then - any good manufacturers then? or is the texecom prestige a sure bet?

*beam me up scotty*

//gets my coat

In my opinion, and it is only an opinion, the choice of manufacturer is often quite personal.

People tend to have their own favourites. Personnally I like Optex detectors but have fitted loads of Texecom PIRs (but not quads) and have found them to be as reliable as any other.

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In my opinion, and it is only an opinion, the choice of manufacturer is often quite personal.

People tend to have their own favourites. Personnally I like Optex detectors but have fitted loads of Texecom PIRs (but not quads) and have found them to be as reliable as any other.

We use quads as well, only problem ive found that on some models of pirs with A/M built in they trip the alarm relay as well as the a/m. Not good on older systems much to the dislike of the callout engineers

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cheers Lawandorder for the vote of confidence- I wasn't aware that trying to converse to others in simple laymans terms was against the rules-If it is then I am sorry!!.

Next time I will try to confound the asker by going in to the complete workings of PASSIVE infra red detectors.

There is totally no need for sarcasm to a reply that was intended to be primarily informative on a basic level. :no:

Regards.

Richard.

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We use quads as well, only problem ive found that on some models of pirs with A/M built in they trip the alarm relay as well as the a/m. Not good on older systems much to the dislike of the callout engineers

I must admit it is difficult to explain how PIRs work without "pretending" that they actually emit a beam.

I once had a branch manager gave me a right roasting for putting two PIRs in the same room facing eachother.

"they will talk to eachother and cause false alrms" he said.

To be fair to him PIRs were fairly new back then and he had a lot of experince with ultrasonic detectors which did interfere with eachother. (missus)

I must admit it is difficult to explain how PIRs work without "pretending" that they actually emit a beam.

I once had a branch manager gave me a right roasting for putting two PIRs in the same room facing eachother.

"they will talk to eachother and cause false alrms" he said.

To be fair to him PIRs were fairly new back then and he had a lot of experince with ultrasonic detectors which did interfere with eachother. (missus)

OOps, meant to quote Rulland there, sorry Rulland.

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Guest anguscanplay

bearing in mind what your conencting these devices too - why not just get the same brand ones, there not bad and have the resisters already in them

if you ask what resisters I`ll scream

pssst we only fit dueltechs if its a wired system

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As already said, most know how a passive works ie not active but i still use the fingers of detection (careful lol) when explaining how the work to customers. Also i also feel its a personal choice. Optex have some fans cos of their lens's and stability. I used to like the aritech's and the alarmcoms due to mirrored optics.

Also a high quality dual edge pir will out perform a cheap quad so choose your sensors wisely. As with most things we all have our favorites either right or wrong, But if you go with any of the brands mentioned you should be fine.

securitywarehouse Security Supplies from Security Warehouse

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pyronixs, do one with a blue light. if you wish to be different B)

Kevin Scott. Owner of KK Alarms...... Installation .. Service .. Repair ...... Thoughout.. Northumberland and North Tyneside ..... Tel:01670 361948 (call diverted after 15 seconds) or 07947444114

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pyronixs, do one with a blue light. if you wish to be different B)

That'll be the kx15dt, pryonix ultras also have blue lights that are so bright after i'd put an alarm in for my dad he didnt have to turn the light on to go to the loo on a night :)

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  • 3 months later...

Let's just break it down for you:

All PIRs have a pyroelectric element.

Most modern PIRs have a dual pyroelectric element which is divided in half. One half gives a positive trigger if a signal is detected, while the other half gives a negative trigger if a signal is detected. These normally cancel each other out in the event of a false alarm. (+1 + -1 =0).

A quad detector's pyroelectric element is divided into four sectors, with two positive and two negative sectors, which are normally diagonally opposed. Which make the detector even more immune to false alarms.

A PIR with two dual pyroelectric elements is often only used in pet friendly detectors and can be quite effective in reducing false alarms in an environment when pets are present.

Most manufacturers also use their own patented algorithms to further reduce false alarms with the above technologies.

A Dual Tech Detector uses two different technologies to detect an intruder. Both of these technologies have different vulnerabilities in terms of false alarm immunity and even further reduce the possibility of false alarms in most instances. The most popular technologies used are PIR and Microwave, but could also use a number of other technologies.

Most PIRs use Fresnel lenses which are generally less expensive to manufacture. Some mirror optic lenses (depending on design) have the advantage to determine size vs distance and can reduce false alarms in this manner.

If you are not going to use a detector with a mirror lens, I suggest that you choose one with a spherical Fresnel lens as this normally focuses better than a flat or bent Fresnel lens, this can define the target better and reduce false alarms. How well would you see an intruder if you had flat or curved flat eyes?

One of the most effective ways of reducing false alarms is a well designed and installed system. You can have the best HiFi system and the best speakers, but if you use cheap or badly installed wiring, your sound will be lacking.

In the same manner a poorly designed and installed system with great detectors will often give you more problems than a professionally installed installation using standard detectors.

Regards

NitroN

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