Basic Elk Wiring question

I have bought a bunch of sensors but not the elk M1 yet since I am just doing wiring at this point. I have motion sensors and door sensors and resistors. Stupid question where does the resistor go and on what color wire on two wire and 4 wire? Also they go right off the door switch or in the motion/smoke detector correct?

Is there a simple wireing guide out there? or is this something that normally comes with the elk directions if so how can I get a copy of the directions?

Here's the install instructions Elk M1G Install Instructions

You'll see arguments both ways, but I believe the "best" way (and the way the manual recommends) is to install the Resistors is adjacent to the sensor (thus the EOL or "End-of Line" name). I haven't wired up smokes or 4-wires myself, but at least in the case of the 2-wire sensors it doesn't matter which color wire you attach it to (when sensor is "open" due to door/window being open, Elk sees an open circuit; when sensor is "closed" due to door/window being closed, Elk sees correct resistance). The manual should show proper connections for 4-wire and smoke detector connections.

Hope this helps...
Autoidiot

You may want to wait until you get the ELK in hand to do the final connections to the sensors. The Elk is shipped with the appropriate EOL resistors, should you want to use them, or so I understand. But what happens if your plans change and you decide to go with Caddx or some other brand? They require a different resistance value than the Elk. Or maybe you will decide to not use EOL resistors.

There are people posting both ways here: Use EOL resistors/Don't use EOL resistors. The only common ground I can see is everyone seems to agree to install them at the furthest sensor in a series-wired circuit. Mounting in the alarm cabinet is worthless.

Photon said:

You may want to wait until you get the ELK in hand to do the final connections to the sensors. The Elk is shipped with the appropriate EOL resistors, should you want to use them, or so I understand. But what happens if your plans change and you decide to go with Caddx or some other brand? They require a different resistance value than the Elk. Or maybe you will decide to not use EOL resistors.

There are people posting both ways here: Use EOL resistors/Don't use EOL resistors. The only common ground I can see is everyone seems to agree to install them at the furthest sensor in a series-wired circuit. Mounting in the alarm cabinet is worthless.

Click to expand...

The only benefit to putting the resistors in the cabinet is not having to go to every device to change them if you swap panels. If you are going to put then in the panel you might as well not use them.

Also is there any specific direction they should go?

Resistors are not direction specific. Do a search with my username for a post I made regarding which side of the zone to install the resistor.

Better yet, do a search for 'EOL' and you will find a ton of threads discussing them, why they are used, how to use them, etc. There is really alot of good info already discussed about them. Personally, I think they are kind of a PITA in a home situation. If you use Normally Closed sensors, and test your opening regularly, you should not need EOL's. But if I were to use them, and starting from scratch, I would probably use the contacts with embedded EOLs.

gatchel said:

Photon said:

You may want to wait until you get the ELK in hand to do the final connections to the sensors. The Elk is shipped with the appropriate EOL resistors, should you want to use them, or so I understand. But what happens if your plans change and you decide to go with Caddx or some other brand? They require a different resistance value than the Elk. Or maybe you will decide to not use EOL resistors.

There are people posting both ways here: Use EOL resistors/Don't use EOL resistors. The only common ground I can see is everyone seems to agree to install them at the furthest sensor in a series-wired circuit. Mounting in the alarm cabinet is worthless.

Click to expand...

The only benefit to putting the resistors in the cabinet is not having to go to every device to change them if you swap panels. If you are going to put then in the panel you might as well not use them.

Click to expand...

Exactly, you use them to help the system determine if the line to the sensor has been "tampered" with, i.e. "cut". If the resistor is at the control rather than the sensor, you can cut all day long and the control just won't know.

"If the resistor is at the control rather than the sensor, you can cut all day long and the control just won't know. "

I don't have an Elk yet, but I'm hopeful that if the line is cut anywhere on a circuit with a normally closed sensor, the Elk identifies an alarm condition on that zone pretty quickly no matter where the EOL resistor is located.

I think the purpose of a single EOL resistor is so the Elk's voltage divider circuit can identify a short circuit, either accidental or intentional. If the EOL resistor is located at the sensor, then a short circuit in the cable leading to the sensor changes the voltage the Elk sees at the zone input. If the resistor is located at the Elk end of the circuit instead, a short anywhere along the line between the Elk and the sensor leaves the resistor in the circuit, so the voltage across the zone input terminals is unchanged, and Elk doesn't respond.

The EOL Resistor at the switch allows for sensing of the circuit open or shorted. Do not put the resistor at the control. It is a waste of a good resistor. In that case program the zone definition as Normally Closed and remove the resistor instead of placing it at the control.

Normally closed zones with no resistor have better noise immunity than EOL wired zones. What you loose with no EOL Resistor is the ability to detect the wires shorted together between the control and the switch. The alarm triggers when the zone circuit is opened with a normally closed zone definition.

If you measure the zone input terminals with a voltmeter on an M1 you will see:

Zone Open: 12 to 13.8 volts DC, must be greater than 9 volts DC.
Zone Shorted: 0 volts DC, must be less than 4 volts DC.
EOL Resistor in place: 4 to 9 volts DC, normally about 7 volts.

"The EOL Resistor at the switch allows for sensing of the circuit open or shorted."

I don't plan to use EOL resistors for my residence, at least not on the window zones. I look at the reed switches on window zones as a convenience to me and for automation more than for security. I intend to use surface mounted magnetic switches with screw terminals. Even if I attach the EOL resistor directly to one of the screw terminals, which pretty much makes it End Of Line, I don't think the ELK can detect a short across the screw terminals in parallel with the NC reed switch, and that would be the easiest place to defeat the system since the screw terminals will be exposed.

I plan to rely on interior PIRs, microwaves, glass breaks, the attack cat, and eventually some exterior sensors, for security. The window sensors will prevent the HVAC from running in a zone with open windows or doors, and will allow Elk to check for open windows when the rain begins.

I don't see how or why an intruder would be trying to open the double-hung vinyl-framed windows. Each window has two very substantial latches. If someone tried to pry them from outside, the vinyl frames would break, along with the glass. Much easier and faster to follow a big rock through the window.

If anyone has experience with the magnetic switches foiling a forced entry attempt, I'd sure like to read about it before I start installing an ELK in a couple months. Same with EOL resistors in a residential application.

Photon said:

"If the resistor is at the control rather than the sensor, you can cut all day long and the control just won't know. "

I don't have an Elk yet, but I'm hopeful that if the line is cut anywhere on a circuit with a normally closed sensor, the Elk identifies an alarm condition on that zone pretty quickly no matter where the EOL resistor is located.

I think the purpose of a single EOL resistor is so the Elk's voltage divider circuit can identify a short circuit, either accidental or intentional. If the EOL resistor is located at the sensor, then a short circuit in the cable leading to the sensor changes the voltage the Elk sees at the zone input. If the resistor is located at the Elk end of the circuit instead, a short anywhere along the line between the Elk and the sensor leaves the resistor in the circuit, so the voltage across the zone input terminals is unchanged, and Elk doesn't respond.

Click to expand...

Should have explained myself a little better.

Here's how to cut all day long on a normally closed circuit without EOL resistors, or resistors at the control panel.

1. Gain access to the wire.
2. Using sharp toothed clamp, clamp wire shorting line (look for the inwire splices and use a jumper wire to do the trick for solid bypass).
3. "Cut all day long" downstream from clamp, eliminating function of normally closed sensor.

Try it on the bench, you'll start to get the EOL resistor reasoning. Granted, one could get very paranoid and have armored conduit to all sensors, but EOL at the sensor and not the panel is a cheaper alternative.

Now you have two conditions that trigger an alarm event.

A. Sensor is triggered and the contact is opened.
B. Wire is cut an a short is detected.

Don't forget the other option... use 4 cond. wire and use the second pair as a return from the last contact back to the panel That way the EOL resistor is both at the end of the line AND at the panel.

When using recessed door/window contact sensors, where does the EOL actually go?

I thought they made pigtallless sensor so you don't need to have any splices in the wall, but how does this take the EOL into account?

Can you buy recessed or other sensors with 'built-in' EOLs? If somebody could post a link that would be great.

MavRic said:

When using recessed door/window contact sensors, where does the EOL actually go?

I thought they made pigtallless sensor so you don't need to have any splices in the wall, but how does this take the EOL into account?

Can you buy recessed or other sensors with 'built-in' EOLs? If somebody could post a link that would be great.

Click to expand...

They are attached to the wire for the contact, then to the contact. Even with direct connect contacts, you will still need a splice if you use EOLs.

The real question is if you should use EOLs or not. Many on this board say always use an EOL; others say that they are not necessary in a residential install. Personally, if a theif is going to go to the trouble to cut a contact wire, that is inside of a wall, they are probably getting in some other way. So, I am on the side that believes that they are overkill for a residential install, plus it makes the install easier. I'm sure others will disagree with this.