M1 Gold Output 2


New Member

Apologies in advance if this has been answered before, i did search the forum but it's still not clear to me how to setup output 2.

I have a self contained siren and it is making a crackling noise when global option 26 is set to siren.

From reading other topics, people have said you should set G26 to siren if you are using a speaker and to voltage if you are using a siren, but why wouldn't you set it to siren using a siren?

Also, since it is "supervised" do i need to install a resistor and if so is that in series or parallel.

One more thing, i also have a siren with a flashing blue light that i need to connect in addition to the previous siren, these are both home runned to the board, will i need to connect this to out 2 as well and does it need a 2.2 kohm resistor?

Thanks for any help and if you need clarification on anything, let me know.
I don't know much about ELK, but be careful to not exceed the current limit of the output. A speaker will probably be the loudest. The output is the same, but for a speaker, the voltage is chopped so it makes a sound, otherwise its just DC. If you do want a siren, its best to drive a relay, then have the relay switch on the siren, but you need a backup power supply for this power source. For it to be supervised, it just measures the current used, probably important for a speaker, but not so much for a relay. There is no resistor, unlike a contact, you are supervising a load. I'd use an outdoor speaker, its easiest. The siren will require some extra work, probably not worth it.
When G26 is set to voltage, the M1 puts out 12V DC power on OUT2 to power a siren unit that has a self-contained driver that produces the sound. When G26 is set to "siren," OUT2 ouputs an audio signal to drive a speaker unit. I agree - it's easy to be confused by Elk's documentation on this. I would have expected G26 being set to "siren" means you have a siren unit attached. Nope - Elk didn't do it that way.

Output 2 can provide up to 1 Amp for an attached siren. If you need more current than that, you'll need an external power supply controlled by a relay as Ano suggested.
Thank you both for your replies, i think I am across it now.

If I understand correctly, say I have 3x 200mA self driven sirens, i could set out 2 to voltage and connect all 3 to 'out 2', and I would be using 600/1000mA?

Also, just confirming, the VAUX terminals on the other side of the board don't affect the 1A limit of 'out 2'? I have 7 PIR's attached across 2 VAUX connections.

Yes, the 3 sirens at 200 mA each would be ok on Output 2.

The VAUX 1-Amp limit is separate from the Output 2 limit. Still, it is possible to exceed the M1's power supply limit of 2.5 Amps total. You need to consider all of the combined loads from VAUX, SAUX, Output 2, the data bus devices such as keypads and expanders, and the M1 board itself. Elk provides a current draw worksheet to make this relatively easy. It will tell you when you need an auxiliary power supply.

If you do, then you need to figure out how to balance the loads between the M1 and the aux supply. You want the aux supply battery to last longer than the M1 battery, otherwise in the event of a power outage, if the aux supply runs down first, the M1 will notice and that may cause problems, such as an alarm condition, depending on what devices are lost.

All of the M1's voltage outputs are protected by individual PTCs, so if you overload them, the output will shut down until the overload condition is corrected.
Last edited: