12V sounder/sirens

[PaulD]

I am interested in monitoring when a sounder or siren is activated to use as a trigger for a seperate action. I know the sounder sound output levels may vary but does that variability come from within the sounder/siren or is it created by variable voltage levels from the generating control board?

I am trying to monitor when a siren is triggered. If I monitor the output from a control board to a siren, will I see a constant 12V signal or a variable level signal? If the voltage varies, what kind of voltage variations (high & low levels) can I expect?

 

[Sandpiper]

I am interested in monitoring when a sounder or siren is activated to use as a trigger for a seperate action. I know the sounder sound output levels may vary but does that variability come from within the sounder/siren or is it created by variable voltage levels from the generating control board?

I am trying to monitor when a siren is triggered. If I monitor the output from a control board to a siren, will I see a constant 12V signal or a variable level signal? If the voltage varies, what kind of voltage variations (high & low levels) can I expect?

It depends. An output to a siren from an alarm board can either be a "speaker" output or a "voltage" output. The Elk M1 output #1 can be configured to do either. However, most alarm boards have only one siren output and is a "voltage" output.

"Voltage" outputs hold a constant 12 volts DC when on and 0 volts when off. "Speaker" outputs have a variable AC voltage which is suitable for directly driving a speaker. This variable AC voltage is the "sound" waveform.

Sound producing devices may either be a "speaker" or a "siren". A siren contains a speaker and a siren driver. The siren driver converts a constant 12VDC into a "sound" waveform with is then fed to the speaker.

So, for most alarm boards, the siren output will be 12VDC when on, and 0 when off. The siren output is sometimes called alarm output, or bell output.

 

[Neurorad]

That was EXTREMELY well explained. Thanks.

 

[dutchyn]

I'm installing an ELK SS15, which accepts two inputs -- yelp and wail -- as well as the ground. I'm considering running output 2 from the M1G through a relay with N/C connected to wail, N/O connected to yelp, COM to output 2, and the ground return with the terminating resistor. That way, the supervised output property is retained, and I can choose which waveform to generate. Maybe wail for fire alarm, and yelp for security.

Comments?

 

[Lagerhead]

I'm installing an ELK SS15, which accepts two inputs -- yelp and wail -- as well as the ground. I'm considering running output 2 from the M1G through a relay with N/C connected to wail, N/O connected to yelp, COM to output 2, and the ground return with the terminating resistor. That way, the supervised output property is retained, and I can choose which waveform to generate. Maybe wail for fire alarm, and yelp for security.

Comments?

So you are going to use Output 3, or something like that, to select the waveform? Certainly Output 3 is convenient and then you don't need an external relay.

Do you need a resistor? IF (in caps because I don't know) the SS15 presents a measurable load to Output 2 whenever the output is idle, THEN Output 2 will be satisfied for supervisory purposes just by connection of the SS15. In this case, it won't matter which you have selected because the relay will always connect one or the other (no other choices) and so always present the SS15 to Output 2 as a load. Therefore, a resistor is never necessary.

If on the other hand you find that the SS15 does not satisfy Output 2 for supervision, I recall Brad saying somewhere that 2.2k is a good choice (which is what I use). In any case, be sure to connect the resistor *in parallel* with the SS15 (i.e. across the terminals and not in-line) (in case you were thinking to do otherwise).

FWIW, I use Output 3 to cut off the outside alarm altogether, for those cases where Elk "overlooked" the fact that outside alarms are sometimes unnecessary or undesirable (e.g., water in basement, septic pump failure). It shunts the output through 2.2k ohms.

 

[dutchyn]

So you are going to use Output 3, or something like that, to select the waveform?

Yes.

Do you need a resistor?

I believe I do need the 2.2K resistor, based on other comments about it being supervised.

FWIW, I use Output 3 to cut off the outside alarm altogether, for those cases where Elk "overlooked" the fact that outside alarms are sometimes unnecessary or undesirable (e.g., water in basement, septic pump failure). It shunts the output through 2.2k ohms.

You can't just provide a rule that says to set output 2 off?

Chris D.

 

[Lagerhead]

I believe I do need the 2.2K resistor, based on other comments about it being supervised.

You can use a resistor. For me, I would rather have the genuine supervision of detecting the attached unit itself, provided of course that Output 2 does "see" the unit when it is idle.

You can't just provide a rule that says to set output 2 off?

Please let me know if you get this to work. I would very much like to save a relay.

Dave

 

[dutchyn]

I believe I do need the 2.2K resistor, based on other comments about it being supervised.

You can use a resistor. For me, I would rather have the genuine supervision of detecting the attached unit itself, provided of course that Output 2 does "see" the unit when it is idle.

My understanding of supervision is that there needs to be a specific amount of resistance (2.2K) indicating the circuit has not become open or short. I find the ELK documentation on sirens, so I don't know for certain if the siren provides that resistance. I've been working under the assumption that placing the resistor between the ground connection of the siren and the cable back to the ELK M1G will satisfy the requirement. Perhaps I can save a resistor if the unit supplies the resistance itself.

You can't just provide a rule that says to set output 2 off?

Please let me know if you get this to work. I would very much like to save a relay.

I'll keep you posted, but it will be a few weeks before I'll have an answer -- we're in the drywalling stage so things are mounted but disconnected.

ChrisD.

 

[Digger]

If I remember correctly anything over 100 ohms will satisfy the supervision of the siren (so 99% of the time the siren itself provides the resistance needed). Keep in mind that only one siren can technically be supervised since the panel cant tell if you have 2 or more sirens connected to one output.