Galaxy 2 intermittent tamper on door sensor

[wilgartw]

hello.

I have a galaxy 2 that I installed about 3 years ago (I now know these are for professionals before you mention it). I know the master code and the engineers code. Everything was ok for about 2 years. Now every couple of months I get a tamper fault, and the box begins to beep at an annoying frequency. I put it into engineer mode for a few hours to silence it, by the time I come to test it (in the evening/weekend) it allows me to come out of engineer mode and cannot see a tamper.

I guess the circuit is deviating to far from the correct resistance, but what is the likely culprit? Should I just replace the sensor? Any advice (except put in a diy friendly system) appreciated.

Thanks

 

[GalaxyGuy]

At the keypad, use 'Display -> Zones' and step with 'A>' to display the zone that is tampering. Then press the hash key on the keypad. The display will show you the circuit resistance. If the resistance is greater than 2k ohms when the door is open or less than 1k ohms when the door is closed, then you can unscrew the sensor to investigate.

To check out your wiring resistance, you can enter engineering mode, then using the same method to view the resistance. You can then short circuit the two zone wires to ensure that the zone shows close to zero ohms. If the wiring looks fine, then replace the sensor.

Other things that can cause issues are:

Alignment issues if Grade 3 sensors have been fitted. Alignment would not be a tamper issue if a grade 2 sensor.
Moisture inside the contact - lowering the resistance.
Bad connection or resistor legs shorting out if resistors have been crammed in an older style contact.

 

[wilgartw]

It is the cellar door.

The door is closed and locked. The display is showing 13.58v 3570ohms
When the door is open it is showing 13.58v and 5015 ohms

When I short the wires it shows 0 ohms

I will get my multimeter out in a second and test the sensor independently

 

[GalaxyGuy]

Just remember, you'll need to disconnect the sensor to test resistance with your meter.

 

[GalaxyGuy]

Also note that different double balanced resistances can be programmed in engineering menu 51.46 Galaxy default is 1k/1k. It may be worth using display zones on another zone with a contact to see if non standard resistors have been used.

 

[wilgartw]

I took the sensor off and tested it.

It showed 1k and 2k.

So I concluded it must be a bad connection. Wired the sensor back up and it is showing 1000 and 2000 on the keypad!

Thanks guys. Much appreciated.

 

[GalaxyGuy]

Okay, great. Glad you're sorted!

 

[wilgartw]

Actually not quite sorted... it occurred to me the original readings should've triggered intruder not tamper.

Then I noticed the zone said 'not used'. I assume I disabled the zone one bleary eyed Morning at 3am when it was reporting a tamper.

Anyway, set it to intruder and now we are sorted!!