Intruder alarm Double Knock facility?

[Rafal]

Hi, Continuing designing my alarm system have I decided on G3 panel. I would like to ask some questions about sensors etc Is Double Knock facility on vibration sensor activated or set from the panel, or is it dependent on the sensor type. The Viper info says: "As an option, Viper can incorporate a double knock facility, once activated the detector will delay responding for 0.2 seconds, if it is reactivated during this time, the attack threshold is exceeded and an alarm signal transmitted"

G3 manual says that you can program any zone on double knock.

If those two are independently set, what sensors would you put on Double Knock? Perhaps PIR in south facing conservatory location?

Thanks Rafal

[Peter In Knowsley]

The vibrations sensor has it's own double knock setting, independent from the control panel. (normally a jumper link)

It's up to you if you want to use this function. Try it and see if it meets your standard.

As to your other question - most panels have double knock facility. Any one involved in the industry (excluding service technicians) would tell you not to use this feature, especially on vibration detectors and door contacts! (one hit and you're in)

If you have to put a pir on double knock, its probably because it false alarms occasionally due to the environment it's sitting in. That means your pir is not suited to it's application. This is not a solution - it just delays the inevitable (more false alarms) or (not detecting an actual break-in). You should find a detector best suited for the job or don't fit one at all.

[Lurch]

On Wed, 28 Apr 2004 22:10:23 +0100, in uk.d-i-y "Rafal" strung together this:

Most detection devices and alarm panels have a double knock facility, you can set it on either or both. If you set it on both then the detector will need to be triggered 4 times in quick succession to activate the alarm trigger so it is only needed to be set on one end, I usually set it in the detector.

Yes, quite right.

Any PIRs that are succeptible to false alarms should be put on double knock, best to set them on single knock then adjust them if they cause a problem. I wouldn't put a PIR in a conservatory, because of the rapid changes in temperature and direct sunlight from all directions it will never be 100% reliable, unless you go for a specialist conservatory PIR. I usually fit glass break sensors to conservatories.

[Rafal]

Thanks, are all pir noisy? Few I looked at recently did make a clicking sound when activated. Also what your opinin on reliability of G3 panel? Just talked to a guy at CSD/Gardiner and he strongly advised me to go for Manvier panel /more expensive obviously/ saying that if you get faulty G3 it sits on the shelf couple of weeks before ADE collects it for repair.

[Lurch]

On Fri, 30 Apr 2004 08:09:46 +0100, in uk.d-i-y "Rafal" strung together this:

Some do, some don't. I've had PIRs from the same batch with a random amount of them clicking. Most are quiet, I'm using Visonics at the moment and they seem to be OK.

I've fitted many G3 panels and I know others who have also, I haven't had any problems with them and I don't know of anyone else that has either.

If money was no object then yes, Menvier would be a nice panel to have but there is nothing wrong with the ADE. For a simple domestic alarm they are ideal, I've fitted them in commercial premises as well with no problems.

[Rafal]

Thanks Lurch

[Lurch]

On Sat, 1 May 2004 00:07:52 +0100, in uk.d-i-y "Rafal" strung together this:

Not a problem. You'll be on a level with alarm engineers soon what with all this knowledge you're soaking up!! It's a pleasure to have someone who listens to advice rather than going off at a tangent then wondering what went wrong!

[Rafal]

Little knowledge is the most dangerous thing. I work in field service industry and often come across people trying to fix things without enough knowledge how they work. Sometimes they will fix it but never properly. Week later somebody else has to go there and spend whole dayy solving the big puzzle created earlier. Thanks again Rafal

[Lurch]

On Sun, 2 May 2004 09:27:54 +0100, in uk.d-i-y "Rafal" strung together this:

Sounds familiar!