Motion Detectors/Elk M1

Mridixon

Member
Replacing my Ademco System with an Elk M1 and now it's time to wire my 2 existing motion detectors to the M1!.  Looking at the wires listed "motion detector" I'm getting a little confused because I see some small resistors on some and it's not the basic 2 wire setup. Do I still need those  resistors? A little advice would help tremendously. Thank you! 
 
Probably 3/4 state wiring.   See the Elk Installation Manual section 1.4  typically optional but allows you to detect things like tamper, etc.    You may need to change the resistor values if  you want it to work with the Elk with those features.
 
You can treat a common motion detector as you do any other two wire sensor excluding power. My motion detectors have two sires for the zone and two sires for 12 volt power.
 
The EOL resistor is for three state zone wiring and not necessary. Two states are open and closed. With two state wiring you can detect sensor open and sensor closed.
 
Three state is open closed and closed with resistance. One way to use three state wiring is to put a resistor in series at the sensor. When the sensor is open the resistance in the loop will be infinite.
When the sensor is closed the resistance will be the value of the resistor used.
When there is a wiring fault as when the two wires are pinched together there will be zero resistance.
 
In this way you are able to detect three states, open sensor, closed sensor and wire fault.
 
Mike.
 
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