Motions and power problems.

["S. Smith" <ChaosLogicXIII@xxxxxxxxx>]

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