Alarm PIR fault

Looking at a fault on a mate's burglar alarm.

When arming a PIR zone has to be omitted because of a "fault".

Tried a different PIR today - no different.

Multimetered the 12v+/- on the 6 core cable (coming out the wall where PIR sited) and nothing showing - though anti-tamper did set alarm off when that PIR case was opened up?

In wiring centre, I can see where the "alarm" connections are for each PIR etc.

2 wires for each zone same colours as seen in PIR. Multimetering these of the dodgy zone, shows one at 13v other at 0v, rest of zones show 5.3v on both...

So is it reasonable to assume wiring to this PIR faulty? (as no 12v+/- at PIR end)??

Any other scenarios? Any other worthwhile tests?

Also - where are the 12v+/- connections likely to be in the wiring centre?? All I can see is a battery & a PCB with plenty connections but no obvious point where all the red and black 12v+/- supplies congregate.... ??

Cheers Jim K

Reply to
Jim K
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sited) and nothing showing - though anti-tamper did set alarm off when that PIR case was opened up?

etc. 2 wires for each zone same colours as seen in PIR. Multimetering these of the dodgy zone, shows one at 13v other at 0v, rest of zones show 5.3v on both...

All I can see is a battery & a PCB with plenty connections but no obvious point where all the red and black 12v+/- supplies congregate.... ??

Jim,

There are usually a minimum of 4 wires connected to a PIR, and often 6.

0v +12v Alarm Alarm Tamper Tamper

Sometimes the alarm and tamper are combined with resistors, so if the panel is presented with different resistance values or open circuit, it can tell the difference between an alarm condition and tamper.

If the PIR is not powered up, then it will be triggering alarm all the time, and opening it will activate a normally closed switch, which will activate the anti-tamper, so I assume your mate's PIR has 6 wires connected.

You say you measured the voltage across the "alarm" terminals on the panel, and it shows 13v on it, I am assuming you had one probe on the 0v rail, and were then testing the two terminals marked zone or alarm - if so, this shouldn't be 13v, it should be the same as the other zones, so it could be a faulty zone on the panel, a faulty PIR or a faulty cable - if you disconnect the wiring to the zone in the panel, and measure again, do you get the same as the other zones on the panel (which you may need to disconnect to compare properly)

It does sound like a wiring issue to me, possibly someone has stapled or nailed through a cable, and has connected the +12v wire to the zone wire(s) in the cable, so best disconnect the power feed to the suspect cable first, otherwise you may short something out when you disconnect the zone wires from the panel, and blow a fuse, which may then lead to the bell sounding if it loses power.

Reply to
Toby

...oh, and a picture of the wiring at the panel might help ID the power feeds, plus the make/model of alarm!...

Reply to
Toby

yup 6 on these:- 12v 0v two labelled (on old PIR) N/C (normally closed alar m contacts?) two labelled T (tamper?)

I'll check that

mmm tho I can't yet locate the point where all the red/black PIR power wire s join... will take a pic of the panel interior and take from there. Typica lly its in a hard to get at location so not knowing how it comes apart to f ind the power supply connections is a bit off putting!!

Cheers Jim K

Reply to
Jim K

Ok so with a working pir zone alarm contacts removed from the panel, checking with multimeter gives exactly the same 13.5,0 readings as the malfunctioning zone, so I'm assuming the panel is ok?

Panel is a texecom 05010 02.05 if pic needed I'll find a way

Ta

Jim K

Reply to
Jim K

No idea what a texecom 05010 02.05 is.

It will probably be an veritas 8, R8 or 8 compact.

It seems that the cable to the sensor is damaged. You either need to replace the cable or as a bodge job rewire the tamper pair of the existing cable to become the +12V and 0V pair and do away with the tamper on that PIR.

Reply to
ARW

Me neither :-D that's what's on the PCB inside the panel.

The keypad is basic non-digital so yup looks like an R8 in their online literature.

Cheers Jim K

Reply to
Jim K

Just sent you the instalation manual.

But this is still IMHO a knackered cable.

Reply to
ARW

+1

If you look in the manual (I don't have this) you may see you can use just two wires for both the zone and the tamper, with either a couple of resistors in the PIR, or sometimes PIR's have these fitted already. It's commonly called EOL, or End Of Line.

You say you can't see where the power cables (to the PIR) connects in the panel yet (Probably marked as AUX on the PCB) - maybe this is the problem, maybe it isn't connected?

Has this PIR ever worked?

Reply to
Toby
6 core wiring would suggest not EOL?

There aren't enough power connections visible for the number of Pirs on the system...

Yes pir used to work, "something" has happened since then, no-one seems to know what when which is a bit suspect to me;-)

Jim K

Reply to
Jim K

know what when which is a bit suspect to me;-)

6 cores means it is not using EOL now, but that doesn't mean the panel won't support it.

On most panels I have seen (Mainly Menvier/Scantronic), you use the outer two connections on the Alarm/Tamper block for the zone, so

A1 A2 T1 T2

Where A is for alarm, and T is for Tamper, you would connect to A1 and T2, leaving the middle two disconnected, but check in the manual that Adam sent you, it should detail if there if it does support it, as different panels also will need different EOL resistors.

It's obvious you have found the correct zone in the panel, as you have measured it - it should be reasonably east to see what cable the wires that are connected to this is, and therefore where the red & black wires are connected - is it is in a really awkward place!?

It is also not impossible to have more then one PIR, or any other detector on the same zone, are all the detectors (including door contacts) still working on a walk test (You may need to bypass the faulty one but connecting the two zone wires together *in the PIR* to test this properly, as this will be triggering all the time!

Reply to
Toby

I'm not changing the tamper to EOL...

If it was easy I would have done it already honest ;-)

Panel is texecom 8 or r8 - anyone know if the PCB comes out easy ? To hopefully reveal the missing connections in choc blocks I would imagine?

Jim K

Reply to
Jim K

How easy do you want it?

Two white plastic "long armed" clips at the bottom of the PCB.

Reply to
ARW

As easy as possible will be fine thks;-)

Jim K

Reply to
Jim K

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