Re: Help with Notifier AFP400 and 3 xp transponders

[Frank Olson <Use_the_email_links@xxxxxxxxxxxxxxxxxxxxxx>]

J Barnes wrote:

> Thank you for the reply, the information you gave was helpful.  The power
> supply problem is fixed :)

Excellent!


>
> This problem with the invalid reply is strange.  Today I installed a new
> XPP1 module but the problem is still there.  This sugests to me it is a
> wiring problem however I have the same voltage on the loop as the working
> transponder.  The other thing is the working transponder is only about 20
> feet from the non working one.  They are both programmed on the 2nd
> addressable loop.  The only thing im not sure of is where the wire goes
> before it gets to the other transponder.  I think ill try running a
> temporary wire from the non working unit to the working unit and see where
> that gets me.

That would be my next suggestion.


>
> The shields on both addressable loops are not grounded at any device,
> including the main control.

There is a "shield terminal".  This isn't part of the system ground
(that I know of), however...  grounding the shield shouldn't result in
invalid responses and if one of the wires was "skinned" you'd wind up
with a ground fault.


> When I grounded #2 at the main control all the
> devices on that loop gave me an invalid reply.  When I grounded the shield
> for loop #1 only one of the devices on that loop gave me an invalid reply.
> I think their may be a wire problem on these loops, but I cant find it with
> a meter.  I tested for shorts from the shield to + and - on the loop but
> none show up.  Do you have any other ideas to find this problem?  Or am I
> faced with pulling every device on the loop to make sure the shield is
> spliced together and not shorting to any equipment.


That's a "toughie".  In most jobs I've been involved in servicing (where
we didn't do the installation), trying to find all the JB's that the
original electrician installed is next to impossible.  If you can solve
the invalid response problem by running a temporary connection between
the two transponders then you're a lot further ahead and the best
solution (from your customer's standpoint) may simply involve installing
a new loop between them.