Alarm terminals

[Grassman]

Hi. Just wanting to add a master blaster siren to an alarm system.
I'm not sure which terminals to connect + and - wires to to trigger it.
Just needs a 12 volt trigger as power for the master blaster comes off 240v separate supply.
Picture of connections below

 

[Highland Mule]

I'd be looking for whatever feed the current bell/ sounder gets. Start at the noisy bit and work backwards, or else just tee into the feed at that point and leave the alarm box alone. There's every chance that the sounder has a constant feed, to keep an adjacent internal battery topped up, and a separate switched live to give an 'all clear' signal (so that you can't silence it by cutting the wire). It may be that the easiest thing is to set it off and have a look whilst armed with a multimeter and ear defenders.

 

[TheTallGuy]

What alarm system is it?

 

[Grassman]

 

[Grassman]

sorry I thought the picture had attached previously.

 

[Grassman]

I assume stb is strobe.
Bell is Bell
Spk is ?
Aux + is ?
So I connect + to either strobe or bell but where does - go?

 

[TheTallGuy]

Without knowing what model alarm you have it's a bit of guesswork, but Spk would be for an external speaker, I would guess that Aux+ is 12V for powering external sounders, strobes, etc. Theres usually a few 0V connections about in alarm panels, but beware that many alarms don't actually provide a 12V output on alarm, rather the output sits high & then switches to 0V during alarm conditions, also be wary of how much current the alarm output will take - some are only 10mA which isn't enough to operate the master blaster relay. If you can tell me what make & model the alarm is I can look it up & see.

 

[Grassman]

Without knowing what model alarm you have it's a bit of guesswork, but Spk would be for an external speaker, I would guess that Aux+ is 12V for powering external sounders, strobes, etc. Theres usually a few 0V connections about in alarm panels, but beware that many alarms don't actually provide a 12V output on alarm, rather the output sits high & then switches to 0V during alarm conditions, also be wary of how much current the alarm output will take - some are only 10mA which isn't enough to operate the master blaster relay. If you can tell me what make & model the alarm is I can look it up & see.

 

[TheTallGuy]

Not worked with one of those before, but looking at the manual it says the output is active low so I believe that output will be at 0V when in alarm state - If you have a multimeter you can check the state of the bell output by measuring across "BELL" and "B-" - if you see 12V under normal conditions and 0V when the alarm is triggered then I would wire the White (Positive ) wire from the master blaster to the "B+" terminal and the White/Black Stripe wire to the Bell terminal. If it's the other way around (0V normal & 12V in alarm) then it would be White to Bell & White/Black Stripe to B-.

 

[Grassman]