Accenta G4 false alarms and double knock

[dunny123]

I have installed Accenta G4 panel with 2 PIRs, one in a portacabin used as an office (zone1), the other (zone 2) in a big wooden shed/workshop which is drafty/may have rat vistors !

Zone 2 alarmed, at 0530 a couple of days after installation. There had been no (human) entry. After reading up on here discovered that drafty sheds with rodents + standard PIR = False alarms, so replaced shed PIR with a dual tech NEXT DUO. All has seemed good since but one week on and had another "falsey" last night at 2200.

I am considering enabling "double knock" on this zone. My only concern is the 10 minute "window" on this system. How exactly does this work, i.e. if for example a real intruder enters, does it mean he can move around for 10 minutes before system generates alarm condition, or does it mean that once PIR has detected intrusion, there is a timer set and some means of interval timer starts ?

Also there is a jumper on the next duo PIR to change the pulse rate, should this be set to faster or slower in this instance ?

 

[breezer]

double knock in this case means the detector must operate twice within 10 minutes to create an alarm condition

if you have vermin then almost any detector will false alarm since it is doing what it is supposed to do.(detecting movement)

if you suspect vermin why not put down a rat trap, and kill it.

 

[dunny123]

Thanks breezer, I get the 10 minutes bit, but in practice when does a trigger from a PIR start and stop ? e.g I am a burglar and double knock is enabled. I break into the shed, the PIR detects me and goes into double knock timer. Can I move around freely for the next 10 mins, or does the first detection last for say 3 seconds and reset and then await a second detection within 10 mins ?

Its a rural area, a woodyard and stables backing onto fields. Use of rat trap not viable as repeat offenders probable !

Actually there is a jumper on this visonic next pir is for event count, 1 or 2, the insructions say use 2 for minimal false alarms, but dont explain how this actually works in terms of timings etc.

 

[breezer]

In this case once a detector has activated once the 10 minute window is started by the control panel.
If the detector then has another activation within 10 minutes an alarm condition is created. If there is no actication for the next 10 minutes nothing happens.

You mention its a visonic detector, i suggest you buy something else, visonic are known to be cheap and unreliable.

You could even swap the two detectors over and see what happens

 

[imigix]

I have installed Accenta G4 panel with 2 PIRs, one in a portacabin used as an office (zone1), the other (zone 2) in a big wooden shed/workshop which is drafty/may have rat vistors !

Zone 2 alarmed, at 0530 a couple of days after installation. There had been no (human) entry. After reading up on here discovered that drafty sheds with rodents + standard PIR = False alarms, so replaced shed PIR with a dual tech NEXT DUO. All has seemed good since but one week on and had another "falsey" last night at 2200.

I am considering enabling "double knock" on this zone. My only concern is the 10 minute "window" on this system. How exactly does this work, i.e. if for example a real intruder enters, does it mean he can move around for 10 minutes before system generates alarm condition, or does it mean that once PIR has detected intrusion, there is a timer set and some means of interval timer starts ?

Also there is a jumper on the next duo PIR to change the pulse rate, should this be set to faster or slower in this instance ?

to avoid false alarms in the type of building you discribe forget movement detectors

use contacts on doors and for the main area use a infra red twin beam unit

this comes in two units a transmitter and receiver

both beams have to be broken to cause a false alarm

so insects and mice and drafts are not a problem

however they are more exspensive £100 or so but there is e bay

 

[breezer]

imigix means two pairs of

A.I.R. Beams

• breezer
• 8 Nov 2008
• 3

Very old A.I.R. beams. <br>A.I.R. stands for Active Infra Red, since unlike a P.I.R. which is...

(but these particular ones are somewhat old)

 

[dunny123]

.......for the main area use a infra red twin beam unit

this comes in two units a transmitter and receiver

both beams have to be broken to cause a false alarm

so insects and mice and drafts are not a problem

however they are more exspensive £100 or so but there is e bay

Sounds a good idea. How do the two beams work, presumably the beams can only be apart by a small amount, how wide are the units ?

 

[breezer]

how do the beams work?

Just like they do on tv

really they do (almost) one shines a light the other looks for it. Likea torch and eyeball, but one is called the transmitter the other the receiver.

So long as the eyeball (receiver) can see the light all is happy.

they should be mounted on a wall not near any flat level suface, this is so that
A) you dont leave anything on the shelf infront of them

B) no vermin can run along said shelf and set it off

as for how far apart, that depends on which ones you get .

the ones shown are ok for about 10m, some are ok up to 150 m

but you have to get them perfectly alined to avoid false alarms , how depends on the brand.

dimensions also depend on the brand, but those shown ar about 5 inches tall

 

[dunny123]

Pretty much as I thought, its just you are talking about two pairs of units, the earlier post was about a twin beam unit. I cant see how the twin beam unit can avoid false detections from say a squirrell or mouse interupting the beams as the beams from such a unit would be far apart enough to achieve this ?

 

[breezer]

thats wy i prefer single units, twin ones are often very close