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Pre-Wired Sensors + Elk M1 Help

drewconner

New Member
My home was built in 1997.  Since purchasing the home two years ago, I have been slowly replacing the light switches, ceiling fans, door locks, etc to be controlled by my ISY-994i.  A few weeks ago, my wife and I decided it would be a good idea to invest in a security system that would work alongside the home automation system.  The Elk M1 was the obvious choice.
 
I purchased the panel, three keypads, wireless and ethernet modules, along with various other expansion boards.  With the help of many posts on this forum, I have successfully installed the board and ethernet modules and can access it from both ElkRP and the ISY-994i's Elk module.
 
My home was pre-wired for a security system, but no actual system was installed prior to the Elk.  As soon as I started connecting sensors to the Elk, I realized that the pre-installed sensors were only one-sided.  They are installed in many door/window frames, but there is no magnet in the doors or windows themselves.  I then purchased some Honeywell Ademco PROBTM magnets because they seemed like they would be easy to install and I assumed the magnets were generally all the same (perhaps incorrectly).
 
My magnets have arrived, but they do not seem to be working with my sensors.  Elk reports all my zones as 13.6v, which tells me that my sensors are N/O with no EOL resistor.  When I place a magnet next to a sensor, I expect the voltage to drop to zero, but there is no change.
 
Can someone offer me some suggestions of what I should do next?  Did I buy the wrong magnets for my sensors?  If so, how can I tell which ones to get instead?
 
Thanks!
 

Linwood

Active Member
A magnet is pretty much a magnet if they are getting close enough.  Do you have a voltmeter/ohmeter that you can check directly at the sensor? 
 
You probably have prewire plugs installed, not contacts. Pull one out and you'll probably find a plug with a loop and the wire tied to it.
 
Contacts are closed circuit devices (electrically deemed NO, though in normal usage they are NC with the magnet in proximity).
 
Plan on buying a batch of contacts.
 

RAL

Senior Member
In some cases, the wiring may be present, but there is no contact installed as well as no magnet.  Are you sure there is really a contact?  Is it visible?
 
If there is a contact, how are you orienting the magnet relative to the contact?  
 
The flat side of the magnet should be facing the round end of the contact, as in the picture below.  If you are trying to place the magnet on the inside face of the window frame, so that it is perpendicular to the contact, that isn't going to work.
 
pro51btm_3_8_inch_stubby_s3429.jpg

 
If you do have the magnet oriented correctly, are you sure you are testing the right set of wires?   Have you tried testing another contact on another window?
 

drewconner

New Member
Thanks all, I knew you guys would know what was up.  I do indeed just have plugs installed and not actual contacts.  The holes are 3/4", so the contacts designed to work with the magnets I have will not fit, although I guess it shouldn't matter.  Do you guys have a recommendation for a brand or a particular model of contact?
 
Contacts don't care what size the magnet is as long as the orientation and alignment are correct....the only place magnet size comes into play is when dealing with a larger gap or a steel door (compresses magnetic field).
 

mikefamig

Senior Member
When you install those sensors you should also install a2.2k EOL resistor in series on each. I don't recall if it should go on the common or the zone lead or if it even matters but I'm sure that someone else here can anwer that.
 
Mike.
 
If the devices are a home run and going on multiple zones, sure, but the return on effort to put an EOLR on a zone with multiple devices in series is far less than a single device per zone.
 
Resistor is installed on the COM or LOW side of the zone.
 
There's plenty of reading on the pros/cons and methodology of EOLR's to keep one reading for a while.
 

mikefamig

Senior Member
DELInstallations said:
If the devices are a home run and going on multiple zones, sure, but the return on effort to put an EOLR on a zone with multiple devices in series is far less than a single device per zone.
 
Resistor is installed on the COM or LOW side of the zone.
 
There's plenty of reading on the pros/cons and methodology of EOLR's to keep one reading for a while.
DEL
 
Can you tell me why it matters which side of the zone sensor you put the resistor? When the sensor is closed there will be approx 2.2k ohms in the circuit and when the sensor is open there will be infinite  resistance regardless of which side the resistor is on. Is it so that you don't reduce the voltage to the sensor when in the closed position? I don't see how it makes any difference.
 
Mike.
 

RAL

Senior Member
mikefamig said:
Can you tell me why it matters which side of the zone sensor you put the resistor? When the sensor is closed there will be approx 2.2k ohms in the circuit and when the sensor is open there will be infinite  resistance regardless of which side the resistor is on. Is it so that you don't reduce the voltage to the sensor when in the closed position? I don't see how it makes any difference.
 
There has been a lot of discussion about this in other threads.  To summarize, if you place the EOL resistor on the positive side of the contact, and a short to ground happened in certain spots, it would go undetected.  The panel would see the proper resistance and think everything is ok, but it would not be able to see the contact opening or closing to trigger an alarm.
 

drewconner

New Member
Thanks again for the replies.  I have ordered the Honeywell 944TSP contacts along with a pack of ELK-9022 connectors for adding the EOL resistors.
 
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