Re: Datalogger to Test False Alarms on Sensor

["Bill" <bill190nospam@xxxxxxxxx>]

Back in the old days... The company I worked for had a customer with a nasty
system which had false alarms which no one could fix.

The police department said "fix it now" or they would quit responding. My
boss assigned me to the job and told me to fix it for free (don't charge
customer) and price was no object!

So I had free reign to resolve this problem. This system had basically one
zone for everything. So first I installed a multiple zone system to isolate
which sensor(s) were causing the problem.

It was the interior photo electric beams.

Next I built my own monitoring gadget which monitored each device and the
electrical power to each device.

Then I got a key to the business from the owner and told our monitoring
center to notify me 24 hours a day if *this* system tripped. Told owner that
no one was to enter building until I got there to examine the lights on my
gizmo. Also told customer how to set my gizmo before leaving.

Well it turned out that the customer was turning off a breaker which powered
the photo electric beams. And the battery would last over a regular weekend.
But would run out of power on a 3 day weekend!

Actually all the alarms were on the 3rd day of a 3 day weekend!

And every time they had an alarm, the owner would come in, turn on all the
breakers for the lights... Alarm service guy would get there and not find
anything wrong.

So the solution to the problem was to tape the breakers which powered the
photo electric beams and write on the tape "Alarm - Leave on". (Something
the installers should have done when installing the system.)

Note: These days there are control panels with enough zones so that you
could have a power monitoring relay for each device on a separate zone as
well as monitoring each device on its own zone. So no need to build any
special "gizmo" like I did.