Adding second sensor to window

I'm a new member so my apologies if this is covered somewhere else.
 
I have a sliding patio door with a single sensor.  I want to add a second sensor so I can vent the window and still have it armed when its open just a bit.  I can get at the wiring for the existing sensor but what I don't know is how do I wire in the second sensor.  I read about end of line resistors but I'm not quite sure how this is implemented or necessary in this situation.  Can I just run the second sensor in parallel to the first one or it there a proper way to do this?
 
Thanks in advance.
 
--Joe

What type of panel are you using?
 
Burglary contacts are NC, EOLs are wired in series with the contact.
If your existing contact has an internal EOL, you'll need a contact with an internal EOL or a separate external EOL.
If your existing contact uses an external EOL, you'll need to wire the new contact in parallel to the old one and ensure you are including the EOL in the series path.
 
How many windows, doors, etc. are on the zone with the slider?
If more than one, the EOL may be located at one of the other portals.
In that case simply wiring the new contact in parallel to the old one will work.
 
If the slider is its own zone, you need to find the EOL and make sure your new contact is wired down stream of it so it maintains continuity through the contact and EOL in both "closed" positions.

jstolzman said:

I'm a new member so my apologies if this is covered somewhere else.
 
I have a sliding patio door with a single sensor.  I want to add a second sensor so I can vent the window and still have it armed when its open just a bit.  I can get at the wiring for the existing sensor but what I don't know is how do I wire in the second sensor.  I read about end of line resistors but I'm not quite sure how this is implemented or necessary in this situation.  Can I just run the second sensor in parallel to the first one or it there a proper way to do this?
 
Thanks in advance.
 
--Joe

Click to expand...

 
You would typically just add a second magnet in this scenario.  Is there some reason that won't work here?

I assumed the magnet is on the door and the switch is probably near the edge of the corner of the upper and vertical jambs, so there's no way to add a second magnet that will make contact with the door ajar.
 
If the contact were in the middle of the track or the upper jamb a second magnet would work.

The existing sensor is in the door frame near the latch. And it is its own zone.  I can get at the wiring if I pull the molding.  So I intend on putting a new sensor along the top of the door and wire it into the existing sensor.  I'm just not versed on whether I just wire them together in parallel as-is, or do I need to add a EOLR at the second sensor.  I'm pretty sure there is no EOLR built into the existing sensor, but there could be one wired in-line.  I'll know more when I pull the door frame.
 
But now you have me thinking,  I can bypass the existing sensor altogether and put the new sensor at the top with two magnets about 6 inches apart.
 
--Joe

jstolzman said:

But now you have me thinking,  I can bypass the existing sensor altogether and put the new sensor at the top with two magnets about 6 inches apart.
 
--Joe

Click to expand...

 
That should work too.