Tying an alarm relay to a siren or light

[GECAMGUY 0]

At the GE Security demo lab, we're attempting to tie in one of the alarm outputs on one of our DVRs to a police-still light-bar, for the purpose of demonstrating when an alarm event occurs.

 

The light bar is a mockup so it requires 110AC not DC like a normal police bar. What we're trying to figure out is, what type of hardware should we use that would allow the alarm out to be able to turn on an electrical source to power the lightbar.

 

Any suggestions?

[securitymonster 0]

should just be a relay. How many amps is the lightbar?

[GECAMGUY 0]

I dunno, I'll have to look, I can't imagine it's high amperage, I'm sure it's a low voltage device.

[CMServices 0]

check out altronix's relay's

http://www.altronix.com/index.php?pid=2&category=16

 

I know they have a relay that workings on dry contacts that will trip and power up 120AC (Police car bar's are 12v DC right?)

if so this relay will work

 

http://www.altronix.com/index.php?pid=2&model_num=RB30

 

I think this relay will help you out with 110AC

 

http://www.altronix.com/p_pdf/RAC120_RAC24.pdf

[CollinR 0]

Does GE still make an alarm control (Caddx)? If so I would wire the DVR as zones NO and supervised. I haven't seen too many DVRs that I would really consider as an alarm. Yeah you can use a regular automotive relay that will suppoer the 12v current, just put the relay after the transformer they installed when they converted the bar to run on 110. Then you have no high voltage issues, if you wire it up NC the light bar will work as normal when not connected to the DVR.

 

 

You will need to bring the 12v from the power source to both the relay's NC side AND through a tiny fuse ~1ma to one of the DVRs relay contacts though some 22-2 wire. Bring the other DVR contact up the other conductor and to the relay's in the light bar's trigger. Unless you have another LV power source (camera system) that you would prefer to use for suppling power to the relay's trigger.

[rory 0]

Bob Clarke should know

[GECAMGUY 0]

Very funny Rory,

 

Bob Clark did in fact give me some suggestions, but I thought I'd ask this group too.

[rory 0]

ive never had to use it with the DVMRe so cant help there sorry ..

[GECAMGUY 0]

No worries Rory, as you can see I got some pretty good suggestions above from the group. We'll figure something out

[kensplace 0]

Dont know what the interface is on the DVR, but make sure if you stick a relay onto it that the back emf from the coil does not blow the DVR output if its not protected.

 

To be safe, you can stick a diode across the coil, in reverse, to absorb the back emf (the current in the coil, that the DVR applied has to go somewhere when the relay is deactivated, and without a diode to short it, it will just shoot back into the DVR as a high voltate.)