Motion detector hookup question

[Ted Birckhead]

I am using an intellisence 7450C Motion detector in NO mode to trigger a
relay that opens a NC delay loop in an old 28 Year old Ademco Alarm.

I would like to update to a new Alarm box and use this motion detector in an
NC mode as another detector in a delay loop. (Other NC switches in the loop
are in doors etc.)

What confuses me is that in the installation brochure at:

http://www.ademco.com.hk/pdf/DT7450 install.pdf

It shows that in the NC mode it indicates 125ma @ 25v DC. I assumed in NC
mode it would only be a dry contact that would open when triggered and not
supply any voltage.

Perhaps I am wrong in that this detector can only be used to trigger a relay
in new alarm boxes?

Thanks for any help-

Ted--

 

[G. Morgan]

alt.security.alarms

I am using an intellisence 7450C Motion detector in NO mode to trigger a
relay that opens a NC delay loop in an old 28 Year old Ademco Alarm.

I would like to update to a new Alarm box and use this motion detector in an
NC mode as another detector in a delay loop. (Other NC switches in the loop
are in doors etc.)

If you get a new panel, it's best to wire the motion detector on a
separate zone by itself (not in series with your doors).

What confuses me is that in the installation brochure at:

http://www.ademco.com.hk/pdf/DT7450 install.pdf

It shows that in the NC mode it indicates 125ma @ 25v DC. I assumed in NC
mode it would only be a dry contact that would open when triggered and not
supply any voltage.

It is only a dry contact, you are correct. The rating is how much
current the contact can handle at the pressure (voltage) of 25V. In
other words.. Don't worry about the contact rating on a modern panel.

Perhaps I am wrong in that this detector can only be used to trigger a relay
in new alarm boxes?

The detector is not triggering a relay in the new "boxes" (they are
called panels). The relay on the detector activates on an alarm
condition, then the panel senses a change in current on that circuit
(zone). Whether or not you use the NO or NC contact on the relay
depends on how you wire the EOL resistor (in parallel or series).

This might sound confusing, but once you see it hooked up it is pretty
simple. Have you decided on which new panel you're getting? If so
download and peruse the installation manual. If you need help
selecting a panel post what features you'd like to have, and describe
all the sensors (burg., fire, environmental, etc..) in the quantity
you will have installed.

 

[Ted Birckhead]

Graham-

Your reply was very helpful, to the point, and easy to understand!
Thanks-
Ted--