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13Owen

Jan 1, 1970
0
I have problem with some systems that have up to 6 detectors in series and
reports of false alarms. The difficulty of cause is determining which
detector us the culprit. I am looking for a solution to this problem. One
idea I had was to use a device I saw year ago from C&K system that they
called a Multiplexer that used different value resistor across each contact
the inturn activated the corresponding relay output. My thought was to then
connect each of the outputs to different input of the alarm system to then
determine where the fault may be. I haven't been able to location such a
device or similar or even another solution alltogether. Can anyone help?
 
J

Julian Vivaldi

Jan 1, 1970
0
whats on the loop?
i often find after years contacts and the wires build resistance and when i
read the ohms i get somethign high like 100 for 3 contacts lets say when it
should be around 4. If i touch the leads to the battery it cleans the wires
and contact, but if the contact is bad or you hold it too long it will blow
it out. Never do this with powered devices. After i do it i always re-read
the ohms and make sure the loop works.
if this is a new install or new work, try opening the device slowly or
trying to trip it and check sensitivity.
 
A

alarman

Jan 1, 1970
0
Julian Vivaldi said:
whats on the loop?
i often find after years contacts and the wires build resistance and when i
read the ohms i get somethign high like 100 for 3 contacts lets say when it
should be around 4. If i touch the leads to the battery it cleans the wires
and contact, but if the contact is bad or you hold it too long it will blow
it out. Never do this with powered devices. After i do it i always re-read
the ohms and make sure the loop works.
if this is a new install or new work, try opening the device slowly or
trying to trip it and check sensitivity.

Jesus.
js
 
A

A.J.

Jan 1, 1970
0
1. Upgrade the main control panel.

2. Home run all motion detectors.

3. Replace all the motion detectors.

It may seem expensive initially, but it will save you and your customers
tons of money not having to pay for 6 false alarm tickets before you nail
down the problem.
 
J

Julian Vivaldi

Jan 1, 1970
0
jesus what?
if your going to say something, say it
id like feedback like everyone else. if you think my practice is bad, tell
me why please.
 
G

G. Morgan

Jan 1, 1970
0
If your reading 100 ohms you have a major problem, touching the loop
to a battery ain't your magic wand. Poor practice.

What you *should* do is wire through all the contacts and short the
EOl, then read the resistance. Eliminate a wiring problem first. If
you get the 1-10 ohm range then, if it's only three contacts, replace
them all.
 
J

Julian Vivaldi

Jan 1, 1970
0
ok lets say im not using EOL and i read 45 ohms for 3 contacts and i use my
practice and i get down to 4 ohms and everything works fine...
luck? stupid answer to bad contacts?
 
G

G. Morgan

Jan 1, 1970
0
ok lets say im not using EOL and i read 45 ohms for 3 contacts and i use my
practice and i get down to 4 ohms and everything works fine...
luck? stupid answer to bad contacts?


I didn't say EOL resistor.

Yes, (stupid answer to bad contacts). Replace them. You might have
unstuck one that is partially welded, but it has a flaw that will
manifest itself again.
 
J

Joe in Bendigo

Jan 1, 1970
0
Sounds like really good advice!
However, I happen to konw that 13owen works on older exisiting government
controlled installations. So without appropriate works approvals upgrading
anything or rewiring anything isn't possible. He clearly needs a method of
either finding a tripping sensor in a series chain or a method of recording
sensor activitiy in order to find whats causing frequent single hits. BTW, I
gather that these are mostly PIR sensors - so it could be anything from
heaters cycling to wandering left-behind pets! -heaven forbid intruders
dashing about the buildings wrapped in aluminium foil :)

Anyone know of a cheap, reliable, small wireless device he could connect
temporarlily to each sensor?

Joe
 
A

alarman

Jan 1, 1970
0
Julian Vivaldi said:
jesus what?
if your going to say something, say it
id like feedback like everyone else. if you think my practice is bad, tell
me why please.

Sorry, you're right. But where do I begin:

You connect a battery to the loop to clear the high resistance trouble?
Clean the wires? How about identifying the high resistance connection or
contact and replacing it. First of all, connecting a high current capacity
battery to the closed loop is dangerous. Also, the current surge when you do
this will most certainly damage any good contacts on the loop. Even if this
works for you, it won't be any kind of permanent repair.

js
 
F

Frank Olson

Jan 1, 1970
0
Joe in Bendigo said:
Sounds like really good advice!
However, I happen to konw that 13owen works on older exisiting government
controlled installations. So without appropriate works approvals upgrading
anything or rewiring anything isn't possible. He clearly needs a method of
either finding a tripping sensor in a series chain or a method of recording
sensor activitiy in order to find whats causing frequent single hits. BTW, I
gather that these are mostly PIR sensors - so it could be anything from
heaters cycling to wandering left-behind pets! -heaven forbid intruders
dashing about the buildings wrapped in aluminium foil :)

Anyone know of a cheap, reliable, small wireless device he could connect
temporarlily to each sensor?



What about replacing the magnets?? If it's a misalignment that's causing the
fault this will fix it for sure. Surely to goodness you guys have rare earth
magnets on your side of the pond... :))

http://www.grisk.com/accessories/rare_earth_magnets.htm
 
A

alarman

Jan 1, 1970
0
Julian Vivaldi said:
jesus what?
if your going to say something, say it
id like feedback like everyone else. if you think my practice is bad, tell
me why please.

Sorry, you're right. But where do I begin:

You connect a battery to the loop to clear the high resistance trouble?
Clean the wires? How about identifying the high resistance connection or
contact and replacing it. First of all, connecting a high current capacity
battery to the closed loop is dangerous. Also, the current surge when you do
this will most certainly damage any good contacts on the loop. Even if this
works for you, it won't be any kind of permanent repair.

js
 
F

Frank Olson

Jan 1, 1970
0
Julian Vivaldi said:
jesus what?
if your going to say something, say it
id like feedback like everyone else. if you think my practice is bad, tell
me why please.


It's very bad practise to short the battery leads (as has already been pointed
out to you). The "high resistance" you might be reading may have to do with
poor connections. Using an "arc welder" to fix 'em is like going rabbit hunting
with a bazooka or fishing with grenades. Sure you can do it... but why would
you want to??

Pull the contacts, fix the problem. GRI is one manufacturer that offers a
lifetime warranty on all their contacts. I don't think that it covers welding
the suckers though.
 
P

Paul

Jan 1, 1970
0
One simple way of determing the problem without any special hard ware is to
temp. bridge out some of the devices. For example, if all of the devices
are Pirs, bypass the relay wiring in each detector. If the fault disappears
at least you have narrowed the problem down. If the devices are reeds then
measure the circuit first and then one by one bridge out the reed switches
until the resistance changes. You can even measure the resistance across the
contacts of each switch to find if you have a high resistance. Just be sure
that if you opt for the first example, the client is aware that their
security will be compromised while some of the devices are being tested and
bridged out and get then to sign to accept the responsiblity.
 
A

Allan Waghalter

Jan 1, 1970
0
Jim's technique is fine. If you use the Loop Stick, however, the resistance
reading becomes an audible sound that you can hear. You take the receiver
around the house with you and essentially do the same thing Jim suggest.
The difference, is you don't need a helper.
Allan
 
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