Re: Motions and power problems.

["J Barnes" <trishnjames@xxxxxxxxxxx>]

    You may have a bad connection on the power + or - somewhere on the run.
It is not unusual to have wires get moisture in the splices and corrode
which will cause a large power drop.  I would start by checking all the
connections at the motion detectors, you may even measure the voltage at
each one to figure out where the drop is the largest.

    I only suggest this because your customer says this setup has worked in
the past.  240ma in standby is not too large of load on the power supply.
Even if all the motions trip at once you are still under the power supplies
rating.

James



"S. Smith" <ChaosLogicXIII@xxxxxxxxx> wrote in message
news:1149377082.400674.93350@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> My company has taken over the monitoring and maintenance of another
> company who has backed out of alarm business to focus on their
> locksmithing.  The system I am troubleshooting is in a warehouse large
> enough to fit a few commercial airplanes in.
>
> The problem we have run into is a series of 10 motion sensors (360
> type, 24mA standby, 42mA max, suspended about 20 ft up).  After tracing
> the lines we found the layout to be one of... well it's just plain
> stupid.
>
> Imagine 10 raidroad tracks approximately 300 ft long (for delivering
> product into the warehouse), a motion placed over each platform and
> between every two tracks. (track, platform, track, track, platform...
> this pattern)  Now we label each track from 1 to 10.  The power supply
> (an old Ademco board pushing 13.5 VDC and 570mA from it's aux power) is
> mounted at the interior end of track one.  The wire leads all the way
> down to track 10, heads to the exterior end of the track, and begins
> powering the motion there.  The series continues all the way to track
> 1.  Talk about taking the longest possible route, eh?  We measure the
> power at track 10 (the first motion in the series) at 11.75 VDC and
> 450mA.  At track 1 the power is 7.5 VDC and 330mA.
>
> Here's the kicker, at first glance the problem seems to be one of
> voltage, despite the motions' operating range of between 6 and 15VDC.
> Yet the warehouse owner (and my supervisor who knows little beyond the
> edges of his desk) insist these motions were a shining example of
> functionality as short as 2 weeks ago.
>
> First of all, I see a major problem with the layout of the 22 awg power
> wire with a run of at least 700ft to it's first device an issue with
> voltage drop has bound to be pre-existing. The #10 motion should have
> enough power to operate at close to it's peak, yet it barely sees a
> person walking around below it.
>
> I want to replace each of these motions with microwave-type sensors
> instead of PIR type as well as placing a new power source at the #5
> track and severing the old one to remove the problem of voltage drop.
> Is there anything I'm missing here?  The biggest obstacle to this plan
> of action is the customer's insistance that they were working and can
> work again.  Can anyone offer something I'm not thinking of?  Thanks
> for all your help in advance.
>
> ChaosLogic
>