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Re: Spacing between NCE BD20 detectors

 

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Before starting my project, I set up a small test bed to make certain that I understood how to wire BD20s together with Atlas universal signal boards.? The first thing it taught me was the importance of checking and double-checking wiring connections. Unfortunately, the test bed was too small to address factors such as distance, ballasting, drops, wiring twists, etc.

On 9/27/21 1:25 PM, thomasmclae via groups.io wrote:

Notice what Alan said, ALL power for the track in the block must go through the BD20.
I have three BD20 on the same module, about 3" apart on separate mainlines.
Two work like a charm, one is always triggered.
I checked the wiring, and the two working BD20 are on track with a single track drop (about 6').
The not working one is connected to track with multiple track drops.
I will be investigating how to have the feed through a single drop.

Thomas
DeSoto, TX

Re: Spacing between NCE BD20 detectors

 

Notice what Alan said, ALL power for the track in the block must go through the BD20.
I have three BD20 on the same module, about 3" apart on separate mainlines.
Two work like a charm, one is always triggered.
I checked the wiring, and the two working BD20 are on track with a single track drop (about 6').
The not working one is connected to track with multiple track drops.
I will be investigating how to have the feed through a single drop.

Thomas
DeSoto, TX
Re: Do any track power boosters have a phase control input?

 

Thanks, Blair. That seems like a solution. I'll have to reread the EasyDCC booster instructions. I think it says not to swap the two DCC signal pins to the booster. I don't know why that would be, if they are truly alike except 180 degrees out of phase!


--
Don Weigt
Connecticut
Re: Do any track power boosters have a phase control input?

 

Lighted rolling stock, passenger cars and other cars that need track power are a scourge to smooth operations. I am a curmudgeon, but when I weigh the need for lighted equipment on a layout that operates 99.9% of the time in daylight, I choose operations over the small gain given by lighted equipment. I can also do without stockcars that moo. Jerry Michels
Re: Spacing between NCE BD20 detectors

 

Buy a creeper!
Re: Spacing between NCE BD20 detectors

 

Do you have other BD20's connected to Atlas' universal signal control board in other areas of your layout that work?

Just this one BD20 is not working?
Re: Spacing between NCE BD20 detectors

 

Bill,

? The typical method for detection placement is for it to be on "the power to the block"
rather than on "the power to one section of the block".? I'll take the time to describe
this further.
? Let's say you have a section of track that has one "power district" that is three
sections of track (with their own feeders) long ... we'll call them A, B, and C.
And each of them has it's own feeders all fed from the same track bus (segment).

? The proper placement of the detector (the "doughnut") is between the booster
and the 'feed' to all three segments ... not in the feed to the "B" (middle) block.
? The idea is to detect all of the power use in the entire track section.??

? Now, if your wiring is too "wimpy" (wire gauge is too small) that can also make
an entire segment (power district) undetectable because the wire is acting as a
"resistor" and limiting the current flow below the level of the BD20 to detect.
? The other problems related to the wiring itself (as have already been hinted at)
are those caused by not twisting the track bus (NOT the feeders) and getting
cross talk between parallel runs of power running to different detection districts.
? The common wisdom is to twist the wire before the detector and not after,
to use larger wire, and to -never- tie wrap or otherwise bring the wires for?
different track segments (detection blocks) running parallel to each other for
even a few inches.? The separation between track bus wires (pairs) should be
at least 3".

? Wiring for signaling is/can be "tricky stuff" and often needs to be 'adjusted'
in each situation and wiring that is perfectly good for a layout without detection
can be unusable when you start adding detection.
? ?If you suspect your wiring then take just one block and?"make it as good as it
can be" with respect to recommended wiring practices (including wire gauge).
If that cures your problem then you know what to do for the rest of the
layout.? When the suspected problem is cross talk (aka "coupling") then
simply unpower all the wires in a bundle except one and see if that one
now works.? However, cross talk can be "cumulative" and elusive to find.
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?- Jim
Re: Spacing between NCE BD20 detectors

 

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Definitely have 5 volts.

On 9/27/21 10:24 AM, John Eldridge via groups.io wrote:

Thanks Bill,?
?
Based on your reply, confirming how this BD20 is connected, you said 3 wires: “one logic, one common, one power”.??
?
Have you measured the “power” voltage @ the BD20 terminals 1 to 4 to confirm you actually have 5V??
?
If you do, you should connect your “logic” wire to pin 3 to take advantage of the power provided.
?
Also, are you saying that with 5V power @ the BD20 terminals, the LED on the BD20 is NOT lighting with a train in the block?

John Eldridge
Texas
Re: Spacing between NCE BD20 detectors

 

Thanks Bill,?
?
Based on your reply, confirming how this BD20 is connected, you said 3 wires: “one logic, one common, one power”.??
?
Have you measured the “power” voltage @ the BD20 terminals 1 to 4 to confirm you actually have 5V??
?
If you do, you should connect your “logic” wire to pin 3 to take advantage of the power provided.
?
Also, are you saying that with 5V power @ the BD20 terminals, the LED on the BD20 is NOT lighting with a train in the block?

John Eldridge
Texas
Re: Do any track power boosters have a phase control input?

 

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Don,

And yes, I realize you're not working with a Digitrax system, but the concept is the same.? However the booster 'learns' what phase of signal to generate, you'll have? to swap the signals.

Blair

On 2021-09-27 10:22, Blair wrote:

Don

In the early days of DCC, I had problems with phasing on my Digitrax layout because I was sloppy with Telco vs Data cables.? Since the only way to 'rephase' a Digitrax booster is to swap the two Railsync signals in the Loconet cable, I'd suggest that an easy solution for you would be to use a 5V DPDT relay to swap the wires that 'inform' the booster as to phase.? Not quite a 'logic level' solution, but certainly 5V compatible. ? The relay could be driven by whatever is powering the turnout, though that might argue for a 12V relay if you're using a Tortoise, for example.

Unfortunately, using a relay may introduce enough of a power dropout that sound locos will reset, but it's a start.

Blair

On 2021-09-27 9:20, Don Weigt wrote:
I've connected up new EasyDCC boosters with auto reversing to my layout. Previously, I used a toggle switch on the panel to control the phasing of the power in the reversing loop.

Auto reversing works reliably, but I've notice some of the metal wheels on old Athearn passenger cars can cause arc after arc as they roll across the gaps. It seems likely only shorts to one side of the booster output triggers auto reversing. I don't like the idea of having this arcing occur over and over. I don't want to use a power relay to switch the phase of the power for the reversing sections. I'd really like a way to control the output phase of the auto reverse boosters.

Does anyone make a booster with a low level, such as 5V logic level, input that controls it's output track power phase?
--
Don Weigt
Connecticut
__._,_._,_
Re: Do any track power boosters have a phase control input?

 

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Don

In the early days of DCC, I had problems with phasing on my Digitrax layout because I was sloppy with Telco vs Data cables.? Since the only way to 'rephase' a Digitrax booster is to swap the two Railsync signals in the Loconet cable, I'd suggest that an easy solution for you would be to use a 5V DPDT relay to swap the wires that 'inform' the booster as to phase.? Not quite a 'logic level' solution, but certainly 5V compatible. ? The relay could be driven by whatever is powering the turnout, though that might argue for a 12V relay if you're using a Tortoise, for example.

Unfortunately, using a relay may introduce enough of a power dropout that sound locos will reset, but it's a start.

Blair

On 2021-09-27 9:20, Don Weigt wrote:

I've connected up new EasyDCC boosters with auto reversing to my layout. Previously, I used a toggle switch on the panel to control the phasing of the power in the reversing loop.

Auto reversing works reliably, but I've notice some of the metal wheels on old Athearn passenger cars can cause arc after arc as they roll across the gaps. It seems likely only shorts to one side of the booster output triggers auto reversing. I don't like the idea of having this arcing occur over and over. I don't want to use a power relay to switch the phase of the power for the reversing sections. I'd really like a way to control the output phase of the auto reverse boosters.

Does anyone make a booster with a low level, such as 5V logic level, input that controls it's output track power phase?
--
Don Weigt
Connecticut

Re: Spacing between NCE BD20 detectors

 

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John,

I'm connecting the BD20s to Atlas' universal signal control board via three wires, one logic, one common, one power.? the Atlas boards in turn have two other posts that use 5 volt power to light the Atlas signal itself.

BIll


On 9/27/21 9:52 AM, John Eldridge wrote:

Hi Bill,?
?
Have been following this topic of your “Spacing between NCE BD20 detectors” question, and have some questions that I have not seen
asked or answered.?
?
1. Are you using a NCE AIU to receive the signal from the BD20 to encode the Block Occupancy to your DCC system? If not, what is your interface?
?
2. If you are using AIU’s to read your BD20's, does the LED on the AIU for the BD20 in question NOT light, while LED’s for other BD20's do light??
?
2. Based on your reply to Don Weigt, am I correct that you are using only Pin 2 “Logic +” terminal + Pin 1 “Ground” on the BD20 to your interface??
?
Please advise, as I have been using BD20's connected with pins 2 & 1 only toAIU interfaces quite successfully for over a year.
?
John Eldridge
Texas
Re: Spacing between NCE BD20 detectors

 

Hi Bill,?
?
Have been following this topic of your “Spacing between NCE BD20 detectors” question, and have some questions that I have not seen
asked or answered.?
?
1. Are you using a NCE AIU to receive the signal from the BD20 to encode the Block Occupancy to your DCC system? If not, what is your interface?
?
2. If you are using AIU’s to read your BD20's, does the LED on the AIU for the BD20 in question NOT light, while LED’s for other BD20's do light??
?
2. Based on your reply to Don Weigt, am I correct that you are using only Pin 2 “Logic +” terminal + Pin 1 “Ground” on the BD20 to your interface??
?
Please advise, as I have been using BD20's connected with pins 2 & 1 only toAIU interfaces quite successfully for over a year.
?
John Eldridge
Texas
Re: Spacing between NCE BD20 detectors

 

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I have heard that adding a resistor to a freight car axle ?and/or caboose also helps with detection. Train length will dictate the number of resistors needed depending upon block length and applications (signals, grade crossings, etc).


On Sep 27, 2021, at 9:23 AM, Bill Wilken <bill.wilken@...> wrote:

?

Don,

I know that adding a 5-volt connection to posts 1 and 4 on a BD20 will permit the onboard LED to light or not depending on block traffic.? I've also read, as you suggest, that it could impact BD20 sensitivity, but I've never found anything to that effect in NCE's documentation.? In any event, it's worth a shot.

Thanks for your feedback.

Bill


On 9/27/21 9:10 AM, Don Weigt wrote:

Bill,

There's often confusion between the terms wire, cable, and pairs. Many people call a multi-conductor cable a "wire", when it's a group of wires. Also, "speaker wire" is really a pair, as is "zip cord." They would usually carry the power and the return; currents in opposite directions, whose magnetic fields approximately cancel.

The BD20 works by detecting the magnetic field created by train current going through the wire threaded through the hole in the detector. That wire becomes part of a transformer. If you put both the power and return wires through the BD20, the currents, going in opposite directions, will cancel each other's magnetic fields. You want only one or the other wires, not both, wound on the BD20. Perhaps that's your problem? Note in the wiring diagram it shows only the power feeder wire, not the return wire, routed through the sensor hole.

Nothing is said about needing a power supply for basic detection. But, I wonder if one might be needed. I've never used a BD20, so I don't know. It would hurt nothing to do this test: Connect a 5V power supply between terminals 1 and 4, as called out for using the onboard LED or an external relay.?Make no other changes. With the 5V power on, does the detector work, and not without it?

Don Weigt
Connecticut

--
Don Weigt
Connecticut

Re: Spacing between NCE BD20 detectors

 

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Don,

I know that adding a 5-volt connection to posts 1 and 4 on a BD20 will permit the onboard LED to light or not depending on block traffic.? I've also read, as you suggest, that it could impact BD20 sensitivity, but I've never found anything to that effect in NCE's documentation.? In any event, it's worth a shot.

Thanks for your feedback.

Bill


On 9/27/21 9:10 AM, Don Weigt wrote:

Bill,

There's often confusion between the terms wire, cable, and pairs. Many people call a multi-conductor cable a "wire", when it's a group of wires. Also, "speaker wire" is really a pair, as is "zip cord." They would usually carry the power and the return; currents in opposite directions, whose magnetic fields approximately cancel.

The BD20 works by detecting the magnetic field created by train current going through the wire threaded through the hole in the detector. That wire becomes part of a transformer. If you put both the power and return wires through the BD20, the currents, going in opposite directions, will cancel each other's magnetic fields. You want only one or the other wires, not both, wound on the BD20. Perhaps that's your problem? Note in the wiring diagram it shows only the power feeder wire, not the return wire, routed through the sensor hole.

Nothing is said about needing a power supply for basic detection. But, I wonder if one might be needed. I've never used a BD20, so I don't know. It would hurt nothing to do this test: Connect a 5V power supply between terminals 1 and 4, as called out for using the onboard LED or an external relay.?Make no other changes. With the 5V power on, does the detector work, and not without it?

Don Weigt
Connecticut

--
Don Weigt
Connecticut

Do any track power boosters have a phase control input?

 

I've connected up new EasyDCC boosters with auto reversing to my layout. Previously, I used a toggle switch on the panel to control the phasing of the power in the reversing loop.

Auto reversing works reliably, but I've notice some of the metal wheels on old Athearn passenger cars can cause arc after arc as they roll across the gaps. It seems likely only shorts to one side of the booster output triggers auto reversing. I don't like the idea of having this arcing occur over and over. I don't want to use a power relay to switch the phase of the power for the reversing sections. I'd really like a way to control the output phase of the auto reverse boosters.

Does anyone make a booster with a low level, such as 5V logic level, input that controls it's output track power phase?
--
Don Weigt
Connecticut
Re: Spacing between NCE BD20 detectors

 

Bill,

There's often confusion between the terms wire, cable, and pairs. Many people call a multi-conductor cable a "wire", when it's a group of wires. Also, "speaker wire" is really a pair, as is "zip cord." They would usually carry the power and the return; currents in opposite directions, whose magnetic fields approximately cancel.

The BD20 works by detecting the magnetic field created by train current going through the wire threaded through the hole in the detector. That wire becomes part of a transformer. If you put both the power and return wires through the BD20, the currents, going in opposite directions, will cancel each other's magnetic fields. You want only one or the other wires, not both, wound on the BD20. Perhaps that's your problem? Note in the wiring diagram it shows only the power feeder wire, not the return wire, routed through the sensor hole.

Nothing is said about needing a power supply for basic detection. But, I wonder if one might be needed. I've never used a BD20, so I don't know. It would hurt nothing to do this test: Connect a 5V power supply between terminals 1 and 4, as called out for using the onboard LED or an external relay.?Make no other changes. With the 5V power on, does the detector work, and not without it?

Don Weigt
Connecticut

--
Don Weigt
Connecticut
Re: Spacing between NCE BD20 detectors

 

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I've been pretty scrupulous about having feeders attached to every section of track.? For my amusement this afternoon, I'll be taking a close look at every wire connection.? Unfortunately, I wasn't sufficiently prescient to build my layout 56" off the floor.? Thinking about kids, I opted for 48", which makes every venture beneath my track work decidedly unpleasant.? Indeed, "build your benchwork 56" high" ought to be the first commandment in any DCC how-to-do-it manual!

On 9/26/21 12:47 PM, wirefordcc via groups.io wrote:

Bill,

I believe you said that your BD20 was not detecting a train in the block.? The pot is for desensitizing the BD20.? So that may not help you.

I did notice in the BD20 instructions where it says it may not work on long blocks.? But it referenced false detections due to couple capacitance and glue and ballast.

Is your long block fed every section or two of track to your bus wires.? Note:? One of your bus wires should be connected to a wire going through your BD20.? Make sure you don't have another connection (called the goober connection!) going to your booster that could be bypassing your BD20.

Those are the obvious things I can think of.

Allan
Re: Spacing between NCE BD20 detectors

 

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Interesting.? Thanks for forwarding.?

On 9/26/21 11:23 AM, David McBrayer via groups.io wrote:

Bill,?
I don’t know all of the in’s and out’s of your layout. ?NCE has an article on their website that discusses a BD20 detection challenge that reads similar to yours at this link,?. Hope this helps. ?

Dave McBrayer?
Auburn, CA?
———————
On Sep 26, 2021, at 07:54, Bill Wilken <bill.wilken@...> wrote:

Allan,

I've tried a variety of "winding" strategies, but without success.? When I talked with NCE's technical support fellow the other day, he was pretty skeptical about the feasibility of 25' blocks.? He suggested that the only viable option was installing a POT on the BD20, which I haven't yet attempted.? In the meantime, I'm double-checking all my wiring.? My experience (successfully) building a test-bed tells me that it's all too easy to goober up connections.

Bill

On 9/26/21 10:45 AM, wirefordcc via groups.io wrote:

Hi Bill,
If you haven't tried it already, try putting more than one turn through your BD20.? Literally just loop it around and go through it again.? This increases sensitivity of the BD20.? I don't think you need multiple detectors in a block.? Check the BD20 instructions for multiple turns through it.

Allan Gartner
Wiring for DCC

--
Dave McBrayer
Auburn, CA

Re: Spacing between NCE BD20 detectors

 

Bill,

I believe you said that your BD20 was not detecting a train in the block.? The pot is for desensitizing the BD20.? So that may not help you.

I did notice in the BD20 instructions where it says it may not work on long blocks.? But it referenced false detections due to couple capacitance and glue and ballast.

Is your long block fed every section or two of track to your bus wires.? Note:? One of your bus wires should be connected to a wire going through your BD20.? Make sure you don't have another connection (called the goober connection!) going to your booster that could be bypassing your BD20.

Those are the obvious things I can think of.

Allan
1941 - 1960 of 14932