I recently added 3 more BDL 168 to a section of my layout. I ready have 25 others that work perfectly. I use Railroad and company to control the layout. The problem Im having is that all my detection sections in this part of the layout go hi and low without any trains or powerdraw. I confirmed this by using loconet checker. This section of the layout has a total of 6 BDL 168s 3 where exsiting and that part of the layout worked perfectly. The 3 exsiting are powered from there own booster. The three new ones have there own booster(DB200). On the other sections in my layout I ran one wire from each BDL terminal to the detection section, all are 14 gauge. This section new section of the layout is used machine control cable that is 18 conductor, 14 gauge that have every conductor numbered, made my life easy so I thought!! Do you thing that this cable is causing the false readings because the conductors are twisted close together or should i be looking for a loconet problem? Im going to start be disconcting everything and putting back one by one but I am curoius to see if any one else has ever seen this problem before. Thanks in advance , Don
That is very likely the cause of the false detection, with all the track power lines in parallel like that. That sort of thing will cause an induced voltage from one wire to another and it doesn;t take a lot to trip the BDL168.
You should be able to easily verify that it's this and not a defective BDL168 by swapping one of the problem ones with one of the others that works fine. If the board is bad, the problem will follow the board, but if it's the wiring, the previously working board will now have the same issue. ANd I highly suspect it's the wiring.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy, after much fuss, I found that I had an bad loconet cable. The loconet repeater would flash ever so often and I found that by jiggling the cable it I could reproduce the error. Its good to know that the multiconductor cable was not the culprit!
Thanks,
Don
At my club, we've had trouble with the BDL's for years. We were told that the length of the wire run plus the track length can set off the BDL dectectors. For example, on a 60' leg of our layout, our single-track mainline blocks are ~15' long. There are four blocks running the length of the 60' leg, with the BDL at one end. Each block has a 14AWG twisted pair under it as a bus, terminated at each end. We ran twin 14AWG to every mainline block's nearest terminated bus, all together through nylon loops. The two circuits closest to the BDL work flawlessly; the two circuits furthest from the BDL are always on.
We're slowly replacing all our BDL's with BOD's from RR-CirKits, as they use toroids to detect current rather than resistance.
I would love to calculate the effective impedance at DCC frequencies from 45-60 feet of twisted pair. If it is above the impedance of what BDLs detect, then yep. I thought though there was a "remote" setup you could do with BDLs. Have you tried before replacing?
Re: the OP's issue -- I think we just have to wait for him to report with an isolated loop from his twisted cable stack.
There are the remote sense diodes you can use with the BDL169, or you can jsut put each BDL168 closer to the blocks it is detecting - there's no reason to line htem all up in oen palce and run dozens of long bus runs from the central point - that kind of defeats one fo the advantages of DCC that you can place the power sources near the point of consumption and run just the control bus lines around the entire layout.