Re: home owner needs advice

["Bob La Londe" <none@xxxxxxxxxx>]

"ABLE1" <nospamhere@xxxxxxxxxxx> wrote in message
news:gBpot.41720$d9.15067@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> "CalT" <calT@xxxxxxxxxxxxxxx> wrote in message
> news:XnsA1CC62B833B83samnonenet@xxxxxxxxxxxxxxxxxx
>>I have some Optex Annunciators protecting my rear laundry room
>> entrances.
>>
>> http://www.optexamerica.com/security-products/rctd-20u
>>
>> I need a siren to be tripped by this to scare any burglar or whomever
>> away before they continue on into my home.  In the Optex manual it
>> says:
>>
>> "Terminal Connection:  Any device with a zero voltage input terminal
>> can be connected to this terminal.  This may include electronic locks,
>> emergency sounding devices, and automatic reporting equipment."
>>
>> I do not understand the term "zero voltage input terminal".
>>
>> When the Optex triggers on movement it senses and the NO terminals
>> close, how can they activate any relay or whatever if the terminals
>> cannot have a voltage applied or current running through them?
>>
>> Somewhere I am not understanding something here.  I am used to hooking
>> up relays in my screwing around over the years, but this has me
>> baffled.
>>
>
> Well un-baffle yourself.
>
> The contacts are just "dry contacts"  aka   no voltage.  You can apply a
> voltage to the C(Common) Terminal and when tripped the voltage will be
> applied to the NO(Normally Open) terminal.  Or voltage will be removed
> from the NC(Normally Closed)
>
> Just be advised that the contacts are only rated at 1 amp @ 50vac and
> 24vdc. More than that you will need a slave relay to handle heavier loads.
> Make sure you check the specs of the device you are connecting to before
> you become unhappy with yourself.  :-)
>
> Hope that helps.
>
> Les

Use it to trigger a low current relay (Elk has one that will trigger at
1.2ma) and/or place a clamping diode across the terminals to protect the
switch on your sensor.