# Occupancy detection, etc. hardware recommendations



## jackpresley

Gentlemen,

I wasn't sure how to get your attention other than a quote, so that's why I included a blank quote blocks below. Hope that's not a foul.

I'm interested in your recommendations (and everyone else's recommendations) for hardware to us with TC for block occupancy/detection, transponding, etc. I have a test layout I want to experiment with that has a three crossings and two merging turnouts.

It is pretty simple but I'm not sure what hardware I need and the books and TCG manual are pretty generic. 

Thanks for the help.
-Jack



Mark VerMurlen said:


> ...





JerryH said:


> ...





fcwilt said:


> ...


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## jackpresley

*Test Layout*

Here is the test layout with the blocks/sections color coded and labeled. (Ignore the 29/38/45 text, that's just so I knew the size of the Unitrack)

So there are two main lines, the two ovals -- and the trains run counter-rotating on these. A train can move from the outer main line to the inner, by turning out in the SW corner. It crosses the inner and the 90* crossing in the middle, and then merges with the inner main line at the turnout.

There are FIVE conflict points: Center 90* crossing, 2 main line crossings, and 2 merging turnouts on each main line.

What hardware do I need to detect satisfactorily for TC when trains are in each of the preceding blocks to these conflict points?

Thanks again. Hope this clarifies my original request.


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## D&J Railroad

I'm using TC Silver and am using the Digitrax BDL168 for block detection and the SE8C for signal control. You will need a reversing system in there for the cross over area.


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## JerryH

I use BDL168s for occupancy detection with TC.


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## JerryH

Also, each piece of rolling stock has a 10K 1/8 watt resistor across one axel between wheels.


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## Lemonhawk

Bxp88 and its reverse loop mate the bxpa1, both detection and transponding. Simple to connect and you get circuit breaker protection. No coils, needed! These are fairly new and replace an assortment of cards.


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## Mark VerMurlen

Hi Jack. Sorry to be slow to reply. I've been out of the country for a couple of weeks.

First a comment on your test layout. You've currently drawn the layout with 12 blocks. However, the two parallel passing tracks at the top of the outside track need to be broken up into at least 2 separate blocks in order for them to work well with TrainController. I've looked closer at your layout and I don't think you need to have any auto reversers. But this does mean you need to wire the polarity of the inner loop opposite of the outer loop. If you were to need auto reversers, the explanation below would be more complicated.

On my system, I'm using two Digitrax PM42s for power management for 8 zones (4 zones per PM42). I'm using two Digitrax BDL168s for occupancy detection (16 blocks each), which gives me the ability to detect 32 blocks. The interesting thing about the BDL168 is that its 16 blocks are grouped as 4 zones of 4 blocks each (zone A feeds blocks 1 - 4, zone B feeds blocks 5-8, etc.). This would be important if you needed auto reversing, which I don't think you do.

If I were to wire this, I'd buy one PM42 and one BDL168. The PM42 would feed the BDL168 to provide circuit breaker protection. You could skip the PM42, but then a short in one place on the layout would bring down power to all blocks.

As Lemonhawk suggested, Digitrax does have new hardware boards for detection. You would need two BXP88s.

Mark


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## jackpresley

Mark VerMurlen said:


> Hi Jack. Sorry to be slow to reply. I've been out of the country for a couple of weeks.
> 
> First a comment on your test layout. You've currently drawn the layout with 12 blocks. However, the two parallel passing tracks at the top of the outside track need to be broken up into at least 2 separate blocks in order for them to work well with TrainController. I've looked closer at your layout and I don't think you need to have any auto reversers. But this does mean you need to wire the polarity of the inner loop opposite of the outer loop. If you were to need auto reversers, the explanation below would be more complicated.
> 
> On my system, I'm using two Digitrax PM42s for power management for 8 zones (4 zones per PM42). I'm using two Digitrax BDL168s for occupancy detection (16 blocks each), which gives me the ability to detect 32 blocks. The interesting thing about the BDL168 is that its 16 blocks are grouped as 4 zones of 4 blocks each (zone A feeds blocks 1 - 4, zone B feeds blocks 5-8, etc.). This would be important if you needed auto reversing, which I don't think you do.
> 
> If I were to wire this, I'd buy one PM42 and one BDL168. The PM42 would feed the BDL168 to provide circuit breaker protection. You could skip the PM42, but then a short in one place on the layout would bring down power to all blocks.
> 
> As Lemonhawk suggested, Digitrax does have new hardware boards for detection. You would need two BXP88s.
> 
> Mark


Yes, I made the drawing too quickly. You are right, there are no reverse loops, and I need more blocks. (I intentionally made it similar to the GGN, as that design will be the basis for the final layout.)

I'm going to have to absorb everyone's responses. Although I'm on vacation now until early June, I'm afraid my time is dominated by the graduation/family reunion/graduation trip so I might not get to tackle this until mid-June.


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## jackpresley

*Simplified Diagram*

Dang, I bought TWO PR4's instead of a PR4 and a PM42. Oops.

Here is a simplified diagram. After I do some reading, I'll be back with more questions on physical wiring and connections.


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## jackpresley

*BXPA1 vs BXP88*

Does the BXP88 do eight times what the BXPA1 does, less reversing? Is the PM42 required if I use the BXP88 or BXPA1?

Confusing documentation (I am easily confused).

If the BXPA1 does everything needed, I can see the simplicity but otherwise why would I pay $50 for one block vs. $150 for 8 blocks?

Thank you for the help.


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## DonR

Jerry

How do the load resistors you install on your
cars for occupancy detection affect the operation
of a DCC reverse loop controller? As you know,
we advise that any isolated track section be longer
than longest train of lighted cars to avoid the last
car truck spanning the 'entry' insulated joiner at same time loco
truck spans the 'exit' joiners. This would result in short circuit.
Would your 'loaded' cars cause the same result?

Don


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## fcwilt

Hi,

My recommended brand is RR-CirKits Simple Serial Bus products.

Pretty much state of art, versatile, easy to install and configure, compact, cost effective and the support is top notch.

They have a device for just about ever aspect of layout automation, etc.

I started with Digitrax gear until someone put my on to RR-CirKits.

Removed and sold all my Digitrax in favor of RR-CirKits.

One thing I really prefer about their approach to occupancy detection is that they use a small coil that you feed one of the block power wires through.

The coil connects to the WatchMan board via small gauge twisted pair. I use pairs from CATx cable.

The advantage of this approach is the power wiring is totally separate from the occupancy sensing so you can optimize each type of wiring. 

Frederick


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## JerryH

Don, I don't know. The auto reversers usually have an adjustment to set the trip point. The total load of the train determines where that should be set. If set too high, the booster breaker will trip first and if too low for the total train load, the reverser will trip more than once.


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## Mark VerMurlen

jackpresley said:


> Does the BXP88 do eight times what the BXPA1 does, less reversing? Is the PM42 required if I use the BXP88 or BXPA1?
> 
> Confusing documentation (I am easily confused).
> 
> If the BXPA1 does everything needed, I can see the simplicity but otherwise why would I pay $50 for one block vs. $150 for 8 blocks?
> 
> Thank you for the help.


Yes, the BXP88 supports 8 times as many blocks as the BXPA1, less the auto reversing. So the only reason to buy the BXPA1 is if you must have auto reversing. It doesn't make economic sense otherwise.

You do not need the PM42 if you use the BXP88 (or even the BXPA1). The new boards incorporate circuit breaker protection themselves without the need of the PM42.

If you do go with Digitrax hardware, for your case, I do think the newer BXP88 is the better option than the older PM42 & BDL168, especially if you don't need auto reversing.

The only time I think the PM42 & BDL168 would be better is if you need multiple blocks within a reverse loop. I think the BDL168 handles that better than the newer boards do, but that may just be my lack of experience with the new boards.

Mark


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## gregc

fcwilt said:


> One thing I really prefer about their approach to occupancy detection is that they use a small coil that you feed one of the block power wires through.


i believe the NCE BD20 is similar and is based on Rob Paisley's Block Occupancy Detector. The transformer is < $2.

But since i'm a DIYer, i've built simpler circuits that are integrated with processor I/O circuits using fewer components.


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## jackpresley

Mark VerMurlen said:


> Yes, the BXP88 supports 8 times as many blocks as the BXPA1, less the auto reversing. So the only reason to buy the BXPA1 is if you must have auto reversing. It doesn't make economic sense otherwise.
> 
> You do not need the PM42 if you use the BXP88 (or even the BXPA1). The new boards incorporate circuit breaker protection themselves without the need of the PM42.
> 
> If you do go with Digitrax hardware, for your case, I do think the newer BXP88 is the better option than the older PM42 & BDL168, especially if you don't need auto reversing.
> 
> The only time I think the PM42 & BDL168 would be better is if you need multiple blocks within a reverse loop. I think the BDL168 handles that better than the newer boards do, but that may just be my lack of experience with the new boards.
> 
> Mark


Okay, thank you for confirming that the BXP88 will do everything I need in one box. That's the way I read it. I think I was confusing the BXP88 with the BDL168 specs.

I think I'll stick with Digitrax for now. I think the BXP88 will do everything I need in one box. So I'll have it and one DS64 quad turnout controller for this layout. Should allow me to cut my teeth.

I need to get it working soon, I came dangerously close to running two brand new expensive locos nearly head on at a 15* crossing.


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## Lemonhawk

The BPX88 replaces the circuit breaker function of the PM42 and does detection and transponding without any additional parts, like current coils or diodes. The BPXa1 is for a reversing loop and again its also the circuit breaker like a PM42. You can't connect the BXP88 up to a reversing loop or even a device that handles reversing loops (PM42, ar1......). So it you were to divide your layout in 8 isolated sections and one reverse loop, you could do that with 1 BPX88 and 1 BPXa1. You would then be able to detect when the locomotive was on any of your 8 isolated sections or the 1 reverse loop. The BXP.. outputs can also send info to signal controllers or JMRI.


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## ronatu

*Have 2 BXPA1 and DS64*



Lemonhawk said:


> Bxp88 and its reverse loop mate the bxpa1, both detection and transponding. Simple to connect and you get circuit breaker protection. No coils, needed! These are fairly new and replace an assortment of cards.


Can you help me with this device?
I am new in DCC-Digitrax and would like to have 2 autorev loops on my layout.
Have 2 BXPA1 and DS64 for turnouts control.
What I do not have is schematic for connections...
PS - see pics


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## ronatu

jackpresley said:


> Does the BXP88 do eight times what the BXPA1 does, less reversing? Is the PM42 required if I use the BXP88 or BXPA1?
> 
> Confusing documentation (I am easily confused).
> 
> If the BXPA1 does everything needed, I can see the simplicity but otherwise why would I pay $50 for one block vs. $150 for 8 blocks?
> 
> Thank you for the help.


Did you find a solution?


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## DonR

Ronatu

I'm a bit confused by your layout drawing.

Have your drawn it out using RED for 'outside' rail,
BLACK for 'inside' rail?

I see the two reverse loops that you have identified,
but the connection 'in red' between T2, T3 and T4 could
also create a 'loop' situation.

Don


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## ronatu

DonR said:


> Ronatu
> 
> I'm a bit confused by your layout drawing.
> Have your drawn it out using RED for 'outside' rail,
> BLACK for 'inside' rail?
> I see the two reverse loops that you have identified,
> but the connection 'in red' between T2, T3 and T4 could
> also create a 'loop' situation.
> 
> Don


Lines for both rails. No outside/inside rails there. Just railroad.
Attached please find simplified version.
2 rev loops there.


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## DonR

What you have is a folded figure eight with a
second figure eight within it. I agree with where
you have indicated insulated joiners but wonder if
those isolated sections are long enough for any
lighted passenger train you might run. If loco is
over 'exit' insulated joiners and a lighted coach truck
is over the 'entrance' joiners you would have a
short circuit. Also, you must use two reverse loop
controllers. You cannot have one control that 'X'
since it would have 4 entrance/exits and the probability
of more than one train attempting to use it
would result in a short circuit.

Don


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## ronatu

DonR said:


> What you have is a folded figure eight with a
> second figure eight within it. I agree with where
> you have indicated insulated joiners but wonder if
> those isolated sections are long enough for any
> lighted passenger train you might run. If loco is
> over 'exit' insulated joiners and a lighted coach truck
> is over the 'entrance' joiners you would have a
> short circuit. Also, you must use two reverse loop
> controllers. You cannot have one control that 'X'
> since it would have 4 entrance/exits and the probability
> of more than one train attempting to use it
> would result in a short circuit.
> 
> Don


Great! 
Don can you help me with simple diagram how to connect two BXPA1 to?
Yours
Roman
See real tracks in attached file


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## DonR

Connecting the BXPA1 is very simple. According
to the Digitrax manual instructions you would see
on it INA and INB. you connect your track bus
to these terminals.

You'll see OUTA and OUTB terminals. These go
to your isolated section.

Phase (polarity) not important as the unit sets that
itself.

You'll need two of these units, one for each isolated
section.

I see by your photo that the X where the isolated
sections are is quite small. You may have short
circuiting problems due this.

If you do, let us know and perhaps we can create
other isolated sections.

Don


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## ronatu

THANKS!


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## ronatu

DonR said:


> Connecting the BXPA1 is very simple. According
> to the Digitrax manual instructions you would see
> on it INA and INB. you connect your track bus
> to these terminals.
> You'll see OUTA and OUTB terminals. These go
> to your isolated section.
> Phase (polarity) not important as the unit sets that
> itself.
> You'll need two of these units, one for each isolated
> section.
> I see by your photo that the X where the isolated
> sections are is quite small. You may have short
> circuiting problems due this.
> If you do, let us know and perhaps we can create
> other isolated sections.
> Don


I did connect bxpa to dcs50 and it worked. However when second bxpa was connected loop stop functioning. 
Is it enough power in DCS50 for 2 bxpa?


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## DonR

Not sure exactly what you mean when you say the
2nd reverse controller stopped functioning.

Did the DCS50 controller show 'short circuit'? How did you
know that reverse controller 'stopped'?

Again there must be a wiring problem. Your DCS50 has
more than enough power for 2 reverse loop controllers.

Recheck that the IN terminals are connected to
the DCS50 (or to the track bus), and the OUT terminals
are connected to the isolated section.

Are you sure you have insulated joiners in both
rails at both ends of EACH isolated section?

As I mentioned in an earlier post, your isolated
sections appear to be quite short. Was there a
train on the isolated section tracks when the
problem occurred?

Don


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## ronatu

DonR said:


> Not sure exactly what you mean when you say the 2nd reverse controller stopped functioning.
> 
> Did the DCS50 controller show 'short circuit'? * - HOW DID THIS LOOKS LIKE?*
> 
> How did you know that reverse controller 'stopped'? *- LOCO DID STOP ON INSULATED TRACK.*
> 
> Again there must be a wiring problem.
> 
> *Your DCS50 has more than enough power for 2 reverse loop controllers. * *- THANKS!*
> 
> Recheck that the IN terminals are connected to the DCS50 (or to the track bus), and the OUT terminals are connected to the isolated section.
> 
> Are you sure you have insulated joiners in both rails at both ends of EACH isolated section?* - YES*
> 
> As I mentioned in an earlier post, your isolated sections appear to be quite short. Was there a train on the isolated section tracks when the problem occurred? *- NO. JUST LOCO.
> *
> Don


THANKS!


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## DonR

I am not familiar with the actual operation of
the DSC50, but it's manual states that a
'short circuit' is indicated by a series of 0's
moving across the screen from left to right.

Did you see those when the loco stopped in the
isolated section? Was the loco spanning the
insulated joiners? 

If you have a multimeter, set it to AC and put
the probes on the rails IN the isolated section that
is a problem after you remove the loco from the
track. You should see around 14 volts.
If you don't see that, there is not feed from the
reverse controller to the isolated section. Some
wire is amiss.

Don


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## ronatu

Don, you are concentration on a wrong idea. 
I am more or less experienced EM engineer and could not mess with wiring (in theory).

As I realized now, one of mine BXPA1 stop working - no red/green light, which I guess signal of occupancy.

Again, is it possible that when I connected both BXPA1 to DCS50 something was happens to its software? How people do troubleshooting BXPA1? 

I am attaching pics with temp test bed for 2 autorev loops.


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## DonR

'

As you are using it, the BXPA is a reverse loop
controller. To test it, connect the track bus to
the two IN terminals. Connect a short wire to
each of the two OUT terminals. Use your meter
set to AC. If the unit is correctly set, you should
see around 14 volts on the two OUT wires. Then
to test that it is switching phase (polarity), keep
your meter on the out wires and put a momentary
but quick short across the wires. The unit is 
sensitive to a short and thus will do a very fast
phase reverse. Your meter should show that the
phase changed. If it did, then the unit it working
correctly. 

I'm not familiar with the various possibilities of the 
BXPA. You might re=read the manual to see that
it is set to be used as a reverse loop controller rather
than a circuit breaker, which seems it may be doing from
your description.

Since your other BXPA is working correctly, you might
compare the settings to make certain they are
the same on the problem BXPA.

When the loco wheels span the insulated joiners
there is a short, the BXPA reverses phase. The loco
continues and when the wheels span the exit
insulated joiners there is another short and
the BXPA again reverses phase to
match the main track.

Digitrax has excellent service. If your tests indicate that
the unit may be defective, go to their website and
use their service. They may be slow in responding, they
had serious damage to their buildings from the recent
hurricane that devestated Panama City, Fl. where they
are located.

Don


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## ronatu

DonR said:


> '
> 
> As you are using it, the BXPA is a reverse loop controller. To test it, connect the track bus to the two IN terminals. Connect a short wire to each of the two OUT terminals. Use your meter
> set to AC. If the unit is correctly set, you should see around 14 volts on the two OUT wires. Then to test that it is switching phase (polarity), keep your meter on the out wires and put a momentary but quick short across the wires. The unit is
> sensitive to a short and thus will do a very fast phase reverse. Your meter should show that the phase changed. If it did, then the unit it working correctly.
> I'm not familiar with the various possibilities of the BXPA. You might re=read the manual to see that it is set to be used as a reverse loop controller rather than a circuit breaker, which seems it may be doing from your description.
> Since your other BXPA is working correctly, you might compare the settings to make certain they are the same on the problem BXPA. When the loco wheels span the insulated joiners there is a short, the BXPA reverses phase. The loco continues and when the wheels span the exit insulated joiners there is another short and the BXPA again reverses phase to match the main track.
> Digitrax has excellent service. If your tests indicate that the unit may be defective, go to their website and use their service. They may be slow in responding, they had serious damage to their buildings from the recent hurricane that devestated Panama City, Fl. where they are located.
> Don


Thanks Don!
Unit was sent back to Digitrax


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## DonR

I assume your tests of the reverse controller showed
it to be defective since you are returning it to Digitrax.

The wiring diagram that you show in your last
post is correct as to the reverse loop controllers.

Don


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## ronatu

DonR said:


> I assume your tests of the reverse controller showed
> it to be defective since you are returning it to Digitrax.
> The wiring diagram that you show in your last
> post is correct as to the reverse loop controllers.
> Don


Also I have notice that DSC50 produced ~23.8V when started, and a few minutes later only 14.8-15V.

Is it normal or my DCS50 is broken (defective)?


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## DonR

The 14.8 volts would be the norm for the output
of a DCC controller.

The electronic experts may have an answer as to
why your controller put out a much higher voltage
initially. Was there a loco on the track when you
observed the high voltage? The no load may be a factor.

I've never had a volt meter connected when I
powered up my controller. I have never seen a variation in light brightness. Double the normal voltage would certainly
cause loco and car lights to go very bright and likely
burn out.

Don


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## ronatu

DonR said:


> The 14.8 volts would be the norm for the output of a DCC controller.
> The electronic experts may have an answer as to why your controller put out a much higher voltage initially. Was there a loco on the track when you observed the high voltage? The no load may be a factor.
> I've never had a volt meter connected when I powered up my controller. I have never seen a variation in light brightness. Double the normal voltage would certainly cause loco and car lights to go very bright and likely burn out.
> Don


High voltage is observed with or without "load". Locos are fine. but I am afraid for another electronic connected to DCS....


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## Hobbytronics

ronatu said:


> High voltage is observed with or without "load". Locos are fine. but I am afraid for another electronic connected to DCS....


Is that something the DCS unit does. The voltage does not change when a load is applied?


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## DonR

This high 'start up' voltagze may be another situation you should discuss with Digitrax.

Don


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## ronatu

Hobbytronics said:


> Is that something the DCS unit does. The voltage does not change when a load is applied?


What exactly DCS50 does??
Load was light 0.1-0.2V drop


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