Burglar Alarm Sensor Question

Comer1

My alarm goes off at random times so I'm assuming a faulty sensor. To find out which sensor is the issue I've opened up the sensors on the affected zone and closed the circuit by joining the black and red cable. I'll leave one operational until the fault starts again and then i'll hopefully have the culprit.

All bar one of the sensors are as below without a resistor. There seems to be no problem closing the circuit on these sensors.

One sensor has a resistor as shown below

I can close the circuit by putting the resistor between the cables as shown below

A few questions please:
1. Why does this one need a resistor?
2. Is what I've done okay?
3. I assume that I will need to use the resistor in any new alarm sensor if that is the problematic one?

Thanks

Lenar3556

It’s a monitoring resistor. The control panel looks to see the resistor is present in the circuit and will display a fault/tamper if the resistor isn’t present.

What you have done to bypass the end sensor is fine. Those sensors are only about €12 each, so it might make sense to change the lot of them.

Nowadays, every sensor would be on its own zone, so it would be obvious which one is at issue.

Comer1

https://www.boards.ie/discussion/comment/123696155#Comment_123696155

Thanks for the reply. I'm taking it slow to determine which sensor is giving the false alarms and it's going very well.

I have a new issue now, the external sounder/siren got water in it on Sunday and now I'm now getting random tamper alarms even when the alarm is not armed. Can anyone recommend a replacement external sounder suitable for the Aritech CS350. I know that the Kinetic Aztech 220 is a good replacement but I can't find anyone who will ship to Ireland. Any help greatly appreciated.

Lenar3556

HKC Saab would be a popular one and compatible.

kub

https://www.boards.ie/discussion/comment/123696155#Comment_123696155

The CS350 panel had to have 1 4k7 resistor connected in parallel with each individual zone input.

Hence the logic there in the single resistor, it does not actually monitor the tamper of that particular zone though as 2 4k7 resistors connected in parallel at an EOL device would be required.

Those particular Aritech GS612 Shock Sensors are no longer at €12 each.

They are actually now closer to €30 per unit, i don't know of any professional still using them, the ideal replacement is the HKC standard sized Inertia Shock, that is around €15 incl vat.

Also as per EN 50131 standards we are allowed to have 10 of these type of sensors per zone input, or say a mixture of shocks/ contacts but cannot exceed 10.

It is wireless devices that have individual identification on Intruder systems

Lenar3556

https://www.boards.ie/discussion/comment/123709298#Comment_123709298

Sure, although I never suggested that it did provide an integral tamper. That system could be heading for 30 years old. It would only be hanging on.

On the cost, the bulk of Carrier business in Ireland (all that is left of it) is direct to a few installers that still use it. I believe it competes favourably with HKC. But any inertia that the OP can get his hands on should be fine.

It may be permitted in the standard, but I haven’t come across daisychained sensors in 25+ years. Why would anyone do that? It makes far more sense to have them wired as individual zones. The OP’s issue wouldn’t arise if they were individually connected.

kub

https://www.boards.ie/discussion/comment/123709447#Comment_123709447

Absolutely but of course back then with a CS350 panel we were only limited to 6 onboard zones of which the first 4 were analysed.

So we were limited back then and daisy chained was of course the way it was done.