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Adding a Lenz BM1 for Automatic Branch line Running


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So I have a route that I want a train to run on, then come back.

 

I have two BM1 modules which I believe will help me do this.

 

I wired them up as per the diagram in the manual but when I came to add power, it just buzzed. Then my PA2 said "overload" so I turned it off.

 

Has anyone fitted these for automated running? Happy to go slow and just get the train to stop before looking at returning it to the other end.

 

I'll try and upload a photo of what I did for testing.

 

Thanks

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2 hours ago, Sir TophamHatt said:

So I have a route that I want a train to run on, then come back.

 

I have two BM1 modules which I believe will help me do this.

 

I wired them up as per the diagram in the manual but when I came to add power, it just buzzed. Then my PA2 said "overload" so I turned it off.

 

Has anyone fitted these for automated running? Happy to go slow and just get the train to stop before looking at returning it to the other end.

 

I'll try and upload a photo of what I did for testing.

 

Thanks

 

Yes they work if fitted correctly.    That you are seeing a short circuit suggests a very basic and fundamental wiring error, because there presence should be invisible to the command station. 

 

Fitting of a BM1 or homemade equivalent to the rails on a single track shuttle line:

 

 

Drawing1.png.c5fc50c1164d1086becf1dae5d5ecca2.png

 

 

 

- Nigel

 

 

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Right hand rule. The rail gaps are always in the right hand rail tommale an isolated section in the direction of normal travel.

Then you need to enable ABC or ADCC in the appropriate CV in your suitable decoder.

The BM1 induces an offset to the DCC signal simulating DC which the decoder reacts to as set.

The diagram above is for an end to end not a loop. A loop would need a further gap tomform an isolated section.

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34 minutes ago, Sir TophamHatt said:

And I guess there will be further connections to my bus wires on the side of the break which isn't the break zone?

 

I think Nigel's diagram shows that, i.e. the connections from the DCC Command Station Track Outputs.

 

Not wishing to hijack the thread but I am wondering where to place the braking zones. I will be running a Pannier tank with an auto coach but also a 3 car DMU and am wondering how this will work.

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43 minutes ago, Sir TophamHatt said:

And I guess there will be further connections to my bus wires on the side of the break which isn't the break zone?

 

If the lines continue beyond the stopping areas - ie. more layout, then an insulating gap at the end of the brake-zone rail, and then any further rails are fed from the normal DCC bus wires.    

If wanting to by-pass the brake zone, fit an single pole on/off switch, so that when "on" (connected) it joins the two terminals of the BM1, and the brake zone receives normal DCC.   Thus "on" means "normal running" and "off" means "brake zone active".  

 

 

Note that whilst BM1 devices have only two connections, there is an "in" and an "out" connection and if you get those the wrong way round, then the brake zone works in the wrong running direction (because you've biased the DCC signal in the wrong direction).  

 

 

 

5 minutes ago, JST said:

 

I think Nigel's diagram shows that, i.e. the connections from the DCC Command Station Track Outputs.

 

Not wishing to hijack the thread but I am wondering where to place the braking zones. I will be running a Pannier tank with an auto coach but also a 3 car DMU and am wondering how this will work.

 

Make the braking zone adequately long, so either loco with its train has plenty of space to slow down and stop.   Then set the various options for stopping distance in the decoder to work for your situation.

 

My experience - if just wanting stopping, then Zimo and ESU do a very good job on constant stopping distance settings.   But, if wanting a shuttle, then the only decoder option is Lenz, and my view is that Lenz have ****ed their constant stopping distance algorithm,  so I just use the normal deceleration (CV4) and run the train at a known to be sensible speed to allow it to stop sensibly in the braking zone. 

 

 

 

- Nigel

 

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Hmm.

So I've set it up again. This time the loco seems to ignore the BM1 and carries on through the brake zone. 

 

I've enabled ABC in the Lenz tab of Decoder Pro. Here's my settings:

 

Constant Braking Diatance: Disabled

ABC: Enabled

ABC Direction Dependanxy: Enabled

PushPull without stop: Disabled

PushPull with Stop: Enabled

Stop on DC: Disabled

Braking distance constant mode: 10

Slow Approach speed with ABC: 8

Push Pull stop time: 4

 

Do I need to change anything else?

 

EDIT:

Okay, so I was powering the insulated "right" rail. Taking that off now causes the loco to stop! Woo!

 

I enabled the 'constant breaking distance' setting.

 

Running at speed 12 or so, it seems to enter the braking section, slow down very quick, then crawl for another 7/8cm before actually stopping.

 

It also doesn't reverse after 4 seconds, which I expected it to unless the speed is set at 28. If the speed is set at 28 then it gets to the middle of the braking section and does a bit of an emergency stop, then reverses.

 

Even more strange is the polarity seems to change. If the loco has done it's stop and reverse then when I want to go forward again, I have to set the controller to reverse.

Edited by Sir TophamHatt
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On 08/03/2019 at 11:49, Sir TophamHatt said:

And I guess there will be further connections to my bus wires on the side of the break which isn't the break zone?

 

All you are doing is isolating a length of right hand rail long enough for the train to stop in and connecting it to one side of the BM1. The other side of the BM1 connects to your main track right hand rail which will be continuous apart from any other stop zones. The BM1 is basically acting as a switch to stop the train using ADCC magic. You can also connect another switch in parallel with the BM1 such as a signal to let the train go when the signal clears by shorting the BM1 terminals.

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Here's some more quick questions:

 

How does the loco know where to stop?

My braking section could be 30cm long, or it could be 2m. Not sure how the loco knows where in the braking section to stop.

 

Is there a way to alter the slow crawl to a defined point? I'd prefer it if the loco just glides to a halt, then reverses. I guess this is the constant braking speed?

 

Also, does the loco travel at the speed I select on the controller both forwards and back again?

 

Thanks

Edited by Sir TophamHatt
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All of the reported Lenz behaviour is normal:  

 

Constant braking distance, yes a Lenz loco follows a curve down, then crawls along at stupid slow pace to the distance point.  I did say Lenz ****ed up their constant braking distance algorithm, you're now seeing that in action. 
Work-around is to use the CV4 deceleration and not use the constant braking setting, then the loco just slows down to a stop, but it won't be at a constant distance.  If you always set the throttle speed to be about the same level, then it will always stop in about the same place.   (Zimo and ESU have nice constant braking distance algorithms that work as one might expect them to, and stop the loco where you want it to stop in a smooth manner.  But they don't do the shuttle option ).

 

 

The loco will begin deceleration when it's last pickup wheel is inside the braking zone.   But, if you have a train with wheels which pickup (can be metal wheels, but will definitely happen with coach lighting), then those vehicles will reset the braking zone as they bridge the insulation gap.  So, the deceleration point will begin when the last vehicle to reset the braking zone has entered the area.   What happens exactly depends on the train in question.   There are ways around the ambiguity of when braking commences:  have a spot detector more than a train length inside the braking area, when the front of the train reaches the spot detector, an electronic connection from detector causes the brake zone to be enabled.    Or, some decoder makers (but not Lenz) offer a setting which can delay braking in one direction for locos on push-pull trains to allow for the length of the train. 

 

 

Loco runs backwards after one reverse.  Yes, Lenz does that.  They do the shuttle by faffing with the normal running direction in CV29.  So, after an odd number of automatic reverse changes, the loco will run backwards.  Fix is to run loco through an even number of reverse changes before taking manual control again. 

 

 

 

- Nigel

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So, fitted to the layout in the same way as my test piece of track. The loco passes the first insulated break and slows down. 

 

However it now won't auto reverse until I hit reverse on the handset.

 

I can't see anything that's different, apart from after the braking zone there's another rail gap and a bit of powered track. I didn't have that on my test track.

 

And I'm now using the Prodigy Advance 2 instead of a sprog. 

 

What could be causing this behaviour? 

Edited by Sir TophamHatt
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