Trane Tracer Summit System

[john07]

Hello
I work at a large prison that has the Trane Tracer Summit building Management system. We have 3 bcm's and a lot of tcm's and ccp's.
It seems that about once a week I come to work and find at least one of the devices has lost communication with the Tracer system. Most of the time the voyager units com card goes bad or a wire is grounded. My question is when it is not a com card, how to tell if the com wire going to the unit is a good circuit? Is there a voltage that can be measured? I have tried checking this on a working unit on ac and dc and did not read anything. I just figured there must be an easier way to test this. If there is a way to test this, is it the same for all devices like voyagers,tcms,ccp's?
Thanks for any help at all
JohnT:)

[roadgear16]

Just to check the integrity of the wire, I would short it either to ground or together, and see if you have continuity, then you can always put a resistor on one end and see if you can read it on the other end.

[scrooloose]

Just to check the integrity of the wire, I would short it either to ground or together, and see if you have continuity, then you can always put a resistor on one end and see if you can read it on the other end.

I would second the resistor idea, throw a 100 ohm on there and you should see the 100 ohm resistor plus the ohms for the length of the wire run.

[mallron]

You should also see anywhere from -2VDC to 2VDC bouncing back, forth and in between. If you disconnect the comm wire from a unit and measure voltage at the comm card you should see about 1.5VDC.