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Motion detector hookup question

Discussion in 'Security Alarms' started by Ted Birckhead, Nov 17, 2004.

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  1. 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: 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-

  2. G. Morgan

    G. Morgan Guest
    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).

    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.

    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.
  3. Graham-

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