Unoccupied track showing as occupied

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#197489 (In Topic #10954)
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Hello all
Quick run down of set up firstN Gauge layout Digitrax based system. Baseboard made up of 2 boards 2mx0.5m layout based on simple double oval. Zephyr feeds into layout where power is split between 4 feeds - 2 point motor feeds, 2 PM42 feeds (1 for each baseboard). PM42's each feed 2 zones for point droppers and 2 zones power BDL168. BDL160 has 7/0.2 wiring going to choc blocks within 15 cm then converted to 32/0.2 which fans out to the layout through a spiders web of connections/wiring no longer than 1.5m. These feeds to track then with 10cm of droppers made of single core equipment wire I think is about 1mm but basically what I had lying around.Layout can be controlled via the zephyr/cabs but will also have automation run via RR&Co Silver. Just finished laying and wiring for the 2 main ovals so time to "test" the track work that is in place and start properly setting up RR&Co for automation.

Right onto the problemManaged to get most zones showing occupancy properly except 2or3 appear to constantly think there is some occupancy therefore some form of current usage. There is nothing visible on the trackwork and the issue is affecting 1 area of the layout but across both boards. I have given it a good going over with a track rubber and some IPA. I initially thought there was a slight current draw through my pva water mix as it was drying where it was on the track as well as sleepers but this is now dry so shouldn't be conducting. The lengths of the wire run's for these areas are at most 0.75m so length of the wire shouldn't be an issue. Does anyone have any thought as to what may be causing this or what I could do to affect/reset this within the system?
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#197490
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Hi Vonk,

Could it be stray capacitance causing the false triggering? How long are the detected sections?

I had a similar problem in 00. I ran some tests by connecting a detected feed to a piece of flexitrack on the kitchen table then adding more sections until there was sufficient capacitance between the rails to trigger the detector. In my case it got moved to the floor and to a length of over 4m before it triggered, but it will probably be much less than that with only 9mm gap between rails. If it isn't that then I'm stuck for other ideas.

Let us know how you get on with Silver, there are several Gold users here.

Regards,

Brian

ECoS, Laptop, TrainController Gold v8
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#197491
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The longest length on the whole layout I have is just over 1 length of flexi with droppers at either end but the affected areas are only about 2ft each section. I have finger x'd it is just residual moisture in the track area as the equivalent areas on the opposite end are fine but were glued a couple of weeks back.I suppose I would have used gold but couldn't justify the extra cost at the moment. Maybe when I win lottery tomorrow I will upgrade :D
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#197493
RFS
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Dampness from the PVA can certainly cause a false indication as it only takes a very little current leakage to trigger the sensor.  You might find that once it's all thoroughly dry it might eventually clear. Took my track a couple of days to dry out and stop triggering the detectors.

But if it doesn't I would double-check that the affected blocks are fully isolated from their neighbours.  A missing IRJ will cause the problem - I had this problem once.

I've recently upgraded from Silver to Gold because there were a few extra things that were nice to have.  But before that I ran very successfully with Silver using full automation so you'll be fine with that to start with.

Robert
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