I asked for a BD20 and they gave me a bagel with cream cheese.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Thank you all for the input and direction. I will go back to determine where the block sections of the trace are next and make the cuts in the track to isolate them into the appropriate sections needed between the signal heads of the two signal bridges I have.
Hmmm, did I misspeak?
OK, in my defense, I am building a new layout, so I was speaking from memory on my old layout.
Now that I think about it, I did what Randy suggested. In those instances where I used more than one pair of feeders, I pigtailed the feeders from one side of rail inside the occupancy block and ran a single feeder from that pigtail through the donut. But that is the point of the BD20 manual. You only run a single feeder through the donut on the BD20.
Rich
Alton Junction
richhotrainhttps://ncedcc.zendesk.com/hc/en-us/articles/201254549-BD20-Block-Detector
For the BD20 to work correctly ALL feeders for the section being detected must go thru the BD20.
greg - Philadelphia & Reading / Reading
If they really mean you can have a poower district with say 10 feeders and you only have to disconnect one of those and run it through the BD20 - that would be the FIRST occupency detection system that works reliably like that. The normal way is that ALL feeders in a detection zone are grouped together with then one wire connecting this sub bus and the main bus passing through the detection device. This is the way all the current transformer detectors have worked since the Chubb DCCOD and otherws. It's the way you are supposed to wire the RR-CirKits current detectors. It's also the way you are supposed to wire the various diode drop detectors like the Digitrax BDL-168 or even back to the original Twin-T detector.
I have never heard of this idea of just putting the detector on one feeder and leaving all the other parallel feeders connected directly to the main bus. You put enough turns through the coil so that a single car with resistor wheels is detected on a piece of track 5 feeders away, a powered loco running over the piece of track where the feeder is the one through the donut hole will likely generate too much current and damage the detector.
It would be nice if they included a wiring diagram other than the loop of wire going through the detector labeled "to booster" and "to track" because I do not think they mean one feeder only while the rest of them in the same detection zone just go directly to the bus.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
gregc i understand what a detector is. and i agree that if enough current from one feeder passes thru it it may work. how many feeders do you typically have. i don't believe that's what the manual recommends, but if it works for you, ...
i understand what a detector is. and i agree that if enough current from one feeder passes thru it it may work. how many feeders do you typically have.
i don't believe that's what the manual recommends, but if it works for you, ...
Here is a link to the NCE site for a discussion of the BD20 and the best practices for wiring it.
https://ncedcc.zendesk.com/hc/en-us/articles/201254549-BD20-Block-Detector
Note that the best practice is to have one BD20 per feeder, and only one feeder per section of track.
gregc BigDaddy "The track feeder wire for one rail of the block is just passed through the hole in the current transformer on the module (see figure 1) before connecting the feeder to the track. does one rail mean just one of the feeders? i assume rail means one of the two rails of the track in that block.
BigDaddy "The track feeder wire for one rail of the block is just passed through the hole in the current transformer on the module (see figure 1) before connecting the feeder to the track.
does one rail mean just one of the feeders?
i assume rail means one of the two rails of the track in that block.
BigDaddy"The track feeder wire for one rail of the block is just passed through the hole in the current transformer on the module (see figure 1) before connecting the feeder to the track.
One feeder per BD20 is what NCE recommends, and I do it with all my BD20s which are used to trigger crossing signals. If more current is required to trigger the BD20 for whatever reason, you wrap the feeder more than once around the donut. Each wrap increases the sensitivity.
gregcthat may work but i doubt it's recommended.
Turns out it is, from the manual.
"The track feeder wire for one rail of the block is just passed through the hole in the current transformer on the module (see figure 1) before connecting the feeder to the track. The more times the wire goes through the hole in the current transformer the more sensitive the detector becomes."
Henry
COB Potomac & Northern
Shenandoah Valley
that may work but i doubt it's recommended.
since the bd20 is sensitive to the amount of current thru it, wouldn't you want as much (all) the current drawn thru the block to go thru the bd20?
gregc But all of the current to all the feeders of that block must go thru the bd20.
But all of the current to all the feeders of that block must go thru the bd20.
the track between each signal or behind a signal needs to be made into blocks with gaps in the non-common rail at each end of the block. the block isn't some number of sections of track. you may have to cut gaps if there's not a conveniently located rail joiner.
the gaps obviously isolate the flow of current between the rails. But all of the current to all the feeders of that block must go thru the bd20. So you may need to create a sub-bus that all the feeders to a block are fed from and a wire between the booster and that sub-block needs to go looped thru the bd20.
if done properly, the bd20 will indicate occupancy whenever a loco or car(s) with resistors occupies the block and draws current thru the bd20.
i think this is more or less what you said. you need to determine where you need blocks protected by the signals.
Henry, you don't necessarily need sub-busses for your BD20s. Power for a BD20 is provided by running a feeder wire off the main bus through the "donut" on the BD20 to the track gapped for occupancy detection.
If I understand your setup correctly, you have four power districts (not counting the fifth power district dedicated to the programming track), but only two power districts control the double mainline, one power district per mainline. If each mainline is going to be divided into four occupancy zones, you will need 4 BD20s, one for each occupancy zone, assuming that both mainlines are to be controlled as one occupancy zone. However, if each mainline is to be controlled as its own occupancy zone, then you would need 8 BD20s.
The BD20 wiring only requires one of the two feeder wires to be wound through the BD20. The other feeder wire in the pair bypasses the BD20 and connects directly from the bus to the track inside an occupancy zone.
In your particular situation, the "main" bus is the bus feeding out of the PM42 to a particular mainline track.
The LION does not do electonics or stuff like that. The block detection of him is designed by a LION with big furry paws. It is bot simple and beastly complicated at the same time.
LION uses reed switches embedded in the tracks, and puts a magnet under the locomotive. (Whe putting a magnet on a locomotive it needs to be as far away from the motor as possible or it will interfere with the operation of the motor)
Because the signal blocks of the lion coinside with the station platforms it flips signal RED as it enters the station. When it enters the next stqtionl, the first signal moves from red to yellow. When it enters the third stqtion the signal moves from yellow to green. The station track cannot take power if the signal in ront of the train is red.
This means a lot of relays, but LIONS *like* relays, the go click when the move, and so the lion can actually SEE where the electricity is going, unlike a little black mystery chip.
Anyway, here is the relay room of the LION:
More information can be fount the the LION's OpsManual.
Hi. I am new and very green to block occupancy (signal) detection and am looking for some guidance. I have an existing layout that currently has 5 main power districts. 4 of the 5 districts are powered through my Digitraxx PM42 circuit board to help keep things running on other districts if one of the 4 districts has a short or power failure. My layout contains two main line tracks with various sidings and a yard. Both main line tracks are each on their own power district (district 1 & 2) buss coming off the PM42 board. The yard is on its own buss (district 3). Power district 4 powers miscellanous regions of my layout. Lastly, district 5 (not powered through the PM42 board, is for my programming track. Each district I either gapped with a dremmel o nthe traces or have insullated rail joiners.
Ok, that giver you an idea of my existing wiring layout (which works great for operation). Now, I have Pensey double track signal bridges (two of them) and all the circuitry to make these bridges work that Integrated Signal Solutions (ISS) provided for me. For the signal bridges to work, ISS provided to me the NCE BD20. I have 7 of these to wire into the layout. I understand I will need sub buses for the wiring and was thinking of doing common wiring (block one rail of the track). Where I want to place each of the two signal bridges spans about 10 feet apart from each other. ISS suggested 4 sections for blocking. But where I get confused is each main line track (track 1 and 2) is running individually, on their own power bus all the way around the layout. So then do I really need 8 block sections, 4 per each main line run of track for this 10 ft span, or really just 4 sections?
Also, if I am to have sub busses for thes power blocks for signal detection would I not need sub buses for each of my main track line buses? so How then would track 1 and track two feed in to one DB20 detector if the given BD20 detecor has to go back to one of the two main bus lines running the entire layout (keep in mind I have two main bus power districts for my main line)?!?!?!?
Any suggestions are GREATLY appreciated as I am really confused and I dont want to start cutting my existing track and/or existing bus power districts up until I fully understand what I need to do.
Thanks,
Henry Vicenik