Bellbox activation

[Guest DaveJ]

Firstly, apologise if I've posted this question to the wrong forum,

Secondly, this may sound like a basic question, but, when a panel goes into an alarm condition through a detector being tripped or entry time out or whatever, how does the bell box know to sound the siren?.

Is it the Bell Hold- that is switched so tripping a relay or is that part of the bell tamper circuit with the SAB TAMP? in the case with Gardtec panels is this also part of the global tamp circuit?

Again sorry if it

[Guest Peter James]

Hi Dave

How the sounder is triggered depends on the panel and the sounder. but most have a trigger from the control panel usually 0v but sometimes 12+

and most control panels have a seperate tamper circuit for bells.

Pete

[Guest DaveJ]

Pete, thanks for the reply.

When you say 0v do you mean that under non alarm conditions it would supply 12v dropping to 0v when triggered and vice versa for a 12v trigger?

I assume the actual trigger mechanism is a relay triggered by either the 0v or 12v trigger from the panel?

All these triggers, sounds like a Del Boy sketch!

Thanks for bearing with me on this Pete.

Dave.

[Guest Peter James]

Hi Dave

(Or should I say Rodney)

Its normally nothing going to 0v to trigger the sounder, some panels have a dry N.O. relay contact going closed in alarm. Some have a transistor driven circuit.

Peter

[Guest DaveJ]

Ta for that Pete, I understand.

"dry N.O. relay" - dry is a new one on me, do you mean no current across the coil ie: just the spring holding the contact open.

Dave.

[Guest Peter James]

Dry means no voltage on the contacts, I.E. you put on the common what you need and when it fires the n/o has the same as what on the common. (i hope that makes sense) You could also say clean contacts it all means the same no voltage.

Pete