I am having difficulty with, seemingly, brief instances of false detection between two adjacent blocks connected to a Digitrax BD4 occupancy detector.
When a loco crosses from BD(section)1 to BD(section)2 all is well. However, some rolling stock (no resistor wheels) crossing the rail gap seem to, just for an instant, cause BD1 to report occupancy. Like a flicker. The upstart of this is that I am using the BD1 and BD2 detection sections (via a DS64 route program) to set a turnout; hence, when the "flicker" occurs, it sets the points back against the direction of travel and derailments occur.
I have changed out the BD4 with a new one and desensitized BD1 and BD2 as shown in the documentation, but to no avail. The joint was recently rebuilt to ensure it was okay. All I can see is the gap in the gapped rail is a bit wider than others on the layout. However, some other detection sections I have with wider gaps and using BDL168 detection work fine. There doesn't seem to be a way to have a BD4 ignore the short pulses of wheels going across the rail gaps. Is there a solution to this or is there another product that handles this situation better?
Thanks, Geoff
The BD4 is notorious for intermittent detection. I would suggest that you find something else to use. There are other block detection devices out there, but they may not interface with the DS64.
I don't know what to suggest for your application. Maybe someone else will know.
Now, since you are using a BDL-168, I assume your connected to a computer. If you are running JMRI, you should be able to use a section or two from the BDL-168 for your detection, and then set up a route in the JMRI route table to change the turnout you want.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Thanks, Elmer . . . your's is some good info. BDL168s aren't economically practical in this situation. The BD4 is being used in a reverse loop out in the attic, hence I don't need (afford) a device for 16 blocks. The only thing I can notice between the application that is failing and the BD4 that works okay is that the reverse loop is about 25' away, whereas the remainder of the layout is within 8 - 10' of the detection devices.
I've heard / seen on some forums some time ago that the capacitance / inductance introduced by long, bundled wires under the layout may contribute to the situation I'm seeing. The key thing here is to have a device that doesn't respond to instantaneous pulses of wheel contact.
Meanwhile, I do use RR&Co. which can, in fact, deal with various hardware discrepancies, however, if I run the layout manually from throttles, I'd like the turnouts to operate correctly. So, if there is something else out there that would work, perhaps someone could advise.
I'm using NCE's BD-20 current detectors for signaling on my T-Trak modules. They are working with relay circuits of my design. The BD-20's work with DCC but I don't know if they'll work with Digitrax's signal systems.
The problem with the BD4's is usually with modern loco's with high frequency drives, including sound loco's. The yahoo digitrax groups covers it. Digitrax fixed the issue in the BDL168 but never did the BD4. One thing that you can try is to separate the Rail A and Rail B wires and keep them a few inches apart. Do not put them in the same wire jacket like you normally would. use single strand wires. Try it with one section and see how it goes. Even the BDL168 with the fix doesn't like distance with the wires together.
Springfield PA
Supposedly BD-4's and BDL-16's and BDL-162's don;t work with supersonic decoders, however this is not the issue here. And on a friend's layout, his automated trolly loop works just fine with a BDL-16, the trolleys all have high frequency drives as do the locos runnign ont he rest of his layout, and the trolley loop does nopt have a dedicated booster, it's just fed by a drop fromt he main track bus through the BDL-16.
One way around this is to not use the input to the DS-64 to directly trigger the route. If you do have a computer and JMRI in the mix for the rest of the detection, use it here as well, JMRI can provide a debounce so that it won't trigger the route over and over again.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
mrnimble When a loco crosses from BD(section)1 to BD(section)2 all is well. However,some rolling stock (no resistor wheels) crossing the rail gap seem to, just for aninstant, cause BD1 to report occupancy. Like a flicker. The upstart of this isthat I am using the BD1 and BD2 detection sections (via a DS64 route program) toset a turnout; hence, when the "flicker" occurs, it sets the points back againstthe direction of travel and derailments occur.
When a loco crosses from BD(section)1 to BD(section)2 all is well. However,some rolling stock (no resistor wheels) crossing the rail gap seem to, just for aninstant, cause BD1 to report occupancy. Like a flicker. The upstart of this isthat I am using the BD1 and BD2 detection sections (via a DS64 route program) toset a turnout; hence, when the "flicker" occurs, it sets the points back againstthe direction of travel and derailments occur.
I may be wrong here but since the wheel is touching both the rail in front of the gap as well as the rail behind the gap causing the problem, why not just make the gap a little bigger and insert a piece of plastic the exact height as the rail head to insulate the gap. Now the wheel will not touch the rail in front nor the rail in the rear as it's rolling over the plastic in the gap. Your turnouts should now behave.
Wadda ya mean I'm old ? Just because I remember gasoline at 9 cents a gallon and those big coal burning steamers.
rrinker Supposedly BD-4's and BDL-16's and BDL-162's don;t work with supersonic decoders, however this is not the issue here. And on a friend's layout, his automated trolly loop works just fine with a BDL-16,........... --Randy
Supposedly BD-4's and BDL-16's and BDL-162's don;t work with supersonic decoders, however this is not the issue here. And on a friend's layout, his automated trolly loop works just fine with a BDL-16,...........
Randy,
What command station is used on the trolley loop? Is it by chance a Zephyr?
Thanks,
Dave
From Mt Pleasant, Utah, the home of the Hill Valley and Thistle Railroad where the Buffalo still roam and a Droid runs the trains
Nope, his whole layout is powered and controlled by a DCS100. He did get a Tam Valley booster to run power to his servo controller turnouts, but that wasn't even in place untilt he trolley loop was automated (RR & Co Traincontroller is what he used, 4 sets of trolleys automatically run around the loop and maintain distance so they don;t run into one another, so the detection has to work).
I originally tried to use JMRI to automate the operation, but the scripting was just way too hard. Plus there is an issue when drawing the track diagram and assigning the detection blocks that you MUST get it right, ie, no mistake and delete a section then redo it, unless youw ant to manually edit some XML to fix it. I noticed occasionally when playing with JMRI that a block ont he opposite side of the loop would sometimes flash occupied when nothign was there. Knowing the supersonic issue, I even reporgrammed the decoder in the test trolley to turn off supersonic drive. No difference, so I put it back since without the trolley hummed badly. RR & Co never had any such issue, we've started up the trolleys and after a 3 hour work session they are still merrily looping about the town and train station, no glitches, no pauses.
Thanks, rockislandnut. I've got a piece of styrene exactly the right size to try this with. Meanwhile, I remain curious as to why other blocks with BD4s don't give a problem - just the two out on the reverse loop in the attic. (??)