Alarm system sensors - re-wiring and testing continuity?

Old 08-18-18, 09:11 AM
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Question Alarm system sensors - re-wiring and testing continuity?

Hi all,

Finally broke down and registered so I could ask some people who may know what they're doing

Anyway, we went from our existing alarm system (Napco-based) to an system, and I got Qolsys' hardwire board to replace the Napco.

However, I found that my system (which only has 5 zones) is set up differently; the Napco has wiring terminals that seem to share a common between zones, so , for example, instead of 2 terminals in Zone 1, it has 1, then another bridging between Zone 1 and Zone 2, then another for Zone 2, and so on.

The Qolsys panel has two terminals solidly in each zone.

So... I haven't figured out how to wire this yet, but disconnected the first few sensors' wires, which are two doors in Zone 1. I added an inline resistor.

I tried reconnecting them, but nothing.

This got me wondering if there's a way to test my magnetic sensors as well as my PIR motion sensors, First thing I tried was continuity, but I'm not actually sure if this would work.

So, it's kind of a two-part question... any help greatly appreciated!

Old 08-19-18, 08:01 PM
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Continuity is the basic test. Hardwired alarm contacts are just switches that are closed when the opening is secure. The difference in wiring is just a design thing. On most standard hardwired alarm systems, _all_ of the common connections are the same, thus you land one wire on the zone input and the other on common, and it doesn't matter if another zone shares the same common, because they are electrically identical. The translator boards, like you have are using isolated zone inputs (essentially the zone is multiple wireless transmitters that share a common board)
Old 08-20-18, 04:45 PM
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Thanks - I'll see if I can figure out a few things based on this.

That said, I haven't found continuity in any wire pairs I've disconnected (6 wires total) but I know for sure that at least a few of them are for my front door.
Old 08-20-18, 06:10 PM
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Could be one of several issues.

One of the devices is open..... door or window.... causing the loop to be open.
The loop is broken/open.
There is an EOL resistor at one of the devices.

Try setting the meter to Rx10 or Rx100 and check again.

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