Re: Configuring CO loop on NX8E

[chasbo@xxxxxxxxx]

I've used this trick ("borrowing" from the power negative terminal) in
cases where a customer wanted an additional Motion Detector near an
existing one, in order to meet my requirement for placing the 2nd MD
on its own zone.

I've also used the same trick when installing a new CO unit above an
existing NX8E Keypad.  I feed the CO with 12vdc from the pad, feed the
negative to the CO relay terminals, and ship the signal back to the
panel on the unused 4th wire of a standard quad cable (keypad only
requires three conductors).

To reiterate my original goal, I'd like to use a four-conductor cable
for alarm and trouble signals for CO Detector configurations, rather
than run extra cable and use up another zone.

but On Fri, 19 Jan 2007 20:34:47 -0500, "Robert L Bass"
<robertbass1@xxxxxxxxxxx> wrote:

>> CO Detectors are available with an
>> internal "trouble" relay, which can
>> be made part of the protective circuit
>> so that when the relay opens its
>> closed contacts (as when the power
>> fails or when the unit fails, etc), a
>> trouble signal at the control panel is
>> the result.
>
>One problem with wiring the trouble relay on the CO detector into the alarm circuit is that a trouble condition at one detector can
>block an alarm at a detector farther from the panel.  You might want to consider using a separate trouble loop, wired to another
>zone.  If you have lots of spare zones at the panel but the wiring is already in place, this can be done using only 4 wires.
>Connect power for the detector in the usual manner.  If the panel uses a common negative for the zone loops, connect positive to the
>appropriate power terminals the negative at the detector to "C" on both the alarm and trouble outputs.  Return "NC" from the alarm
>amd trouble relays on the two remaining wires.