Help trobleshooting Cartell vehicle probe

[PlanoMike]

I have a Cartell vehicle probe under my driveway connected to my Elk M1. It has worked great for several years. I noticed a few weeks ago that it had stopped working. Around this time two things happened which may have started the problem:

(1) Severe storms in the area with a lot of lightning
(2) Verizon installed FIOS and buried a cable into the house in close proximity to the Cartell cable.

I suspect that the cable for the vehicle probe got cut when (2) happened, but before I dig it up, I'm looking for troubleshooting advice.

If I look in my Elk software, it shows a status of "short" for that zone. I have tried rebooting the probe by powering down and powering back up with no improvement.

If the cable were cut, would you all expect the Elk status to show short?

TIA

Mike

 

[BraveSirRobbin]

Mike, do you have a link to the unit? I'm guessing that it has a contact closure if a vehicle is near and open circuit if not (or vice versa). Does it require power?

If it only provides contact closure the best way to trouble shoot this would be with a meter measuring resistance. Disconnect the sensor from the Elk, take a reading with a meter and note the resistance. Then move the vehicles and see if this changes. I'm guessing it does not.

Then you will have to somehow get to a cable end of the sensor and do these same tests. You will have to find a point where these tests work (along that cable run).

If you know where they possibley damaged the cable, maybe go slightly before that point, cut into the cable, and perform these tests.

Hopefully you will find a point where these tests are successfull.

Now don't connect the wiring to the sensor just yet as you have to trouble shoot the cable running from the Elk to the point that you cut.

Again with nothing hooked to either end of the cable measure the resistance between the conductors. They should show open or infinite. Now place a jumper on the Elk end and it should show a reading around five ohms or so (depending on cable length).

You will have to perform these tests on the cable (cut into it at various points) until these readings are correct. This will prevent you from having to perform a full run from the Elk to the sensor.

Hope this made sense (and that I typed that out correctly as I did this quickly)

 

[BraveSirRobbin]

Hey, BTW, if that didn't make sense, glance over my Security System Install How-To as I go more in-depth on cable troubleshooting there.

EDIT: Carefully re-read your post and noted that it indeed takes power to the sensor. Is the fuse blown?

If it is contact closure, you can trouble shoot the zone input like I stated above.

If there is no power or all the conductors are shorted/opened as a result of damage from digging, you will have to trouble shoot the cable until you find this area.

In this case you will have to unhook all the conductors (including the power).

 

[WayneW]

If the cable were cut, would you all expect the Elk status to show short?

A "clean" cut should show as an open. But an accidental cut is possibly messy with the two wires shorted together where they ripped the insulation off.

 

[PlanoMike]

Well, I dug out the cable (actually I hired some poor soul to do so in this heat) and lo, the cable had no evidence of damage.

So on a whim I connected the sensor wires to another input on my ELk and VIOLA! IT is working again. I haven't tried reconnecting it back to the port it was on originally, but I am now assuming that port on the Elk must have gotten blown in the recent electrical storms...is that possible?

At any rate, I am a happy camper (other than being out the cost of digging out the cable!).

Thanks for everyone's help!

 

[PlanoMike]

It appears that I spoke too soon. After working for a time, my vehicle sensor is back to showing short all of the time, now on a different input on the Elk. I'm now thinking I've got a bad sensor.

Does anyone have any other suggestions?

 

[BraveSirRobbin]

Take the sensor off of the Elk input, then see if the short goes away (just to verify it's not the Elk, which I'm sure it is not).

Measure the output of the sensor with a resistance meter and try to see if the sensor is working at all (move a vehicle, see if resistance changes). Check power to the sensor.

The only other thing you may want to do is eliminate the cable as a source of the problem. You might want to cut the cable near the sensor (as close as possible), take a power source to temporarily power it, and see if it works with a resistance meter on the output (detect a vehicle).

If it doesn't work from there, then it's probably the sensor.