Asymmetric braking problems

[Nigelcliffe]

2 hours ago, LNERGE said:

I'm having a problem with a different manufacturers decoder. Everything so far has been with Zimo decoders. I thought I'd try another manufacturer that offered a plug in stay alive facility.

 

I can get the loco to stop at a signal. If I take it off the track and turn it round and reverse the controller so it is going the same way as when I started it fails to stop. Cv27 is set to 1. Am I missing something?

 

 

 

Maybe you're missing something.   But anyone trying to answer is definitely missing something.   You say "I'm having a problem with a different manufacturers decoder", then don't tell us which manufacturer.   So, advice is impossible.   The CVs to control ABC braking are not part of any standards, so makers can do their own thing.  

 

- Nigel

 

 

[LNERGE]

It's a DCC Concepts Zen Black 8 or 21 pin. I have two doing the same thing.

[Nigelcliffe]

13 minutes ago, LNERGE said:

It's a DCC Concepts Zen Black 8 or 21 pin. I have two doing the same thing.

 

DCC Concepts decided that the way everyone else (Lenz/ESU/Zimo/etc.) had done ABC for a decade or more wasn't for them.  So they came up with their own way.  Mixing both can get into difficulties, particularly with slow approach which is incompatible between the two.    I think braking to a stop should be workable with a mixture of decoders, but not tried it to be sure.    

 

Only for DCC Concepts ABC  with RH rail positive biased (ie. a normal ABC diode module fitted to the RH rail as loco is travelling)

CV27=1 is braking only in forward direction of loco with .  ie. no braking in reverse direction.     What you have seen is what DCC Concepts intended.  

CV27=2 is braking only in reverse direction of loco.  

CV27=3 is braking in both directions of loco.

 

 

 

- Nigel

 

 

  

[LNERGE]

If it goes round the reverse loop it works on the other road. If i set it back over the crossover before the reverse loop it barrels past all the signals. No success with settings 2 nor 3.

[Nigelcliffe]

1 hour ago, LNERGE said:

If it goes round the reverse loop it works on the other road. If i set it back over the crossover before the reverse loop it barrels past all the signals. No success with settings 2 nor 3.

 

As I said, DCC Concepts decided to do their own thing with ABC, and quite a bit of what's in their manual describes things which are different to the way Lenz/ESU/Zimo (and others) have traditionally done it.   There are going to be incompatibilities.  

    
You'll need to establish systematically what works in both loco forwards and loco reverse, over a brake devices, with each of the CV settings in the Zen decoder.   If you can't get an acceptable set of behaviours for a loco, then the Zen decoders are not compatible with your layout infrastructure.    

 

Whilst not "plug in", adding a stay-alive to Zimo or ESU is simple.  On the MTC-21 socket, the stay-alive can be wired to the loco PCB (assuming pads are accessible in the loco).  On an 8-pin, the stay-alive would need to be attached to the decoder's solder pads.  

 

 

[LNERGE]

Many thanks.

 

If i can only make it work in one direction then the chips are ending up in a twenty or a or a D82xx so i know at a glance which way round they are and thus unlikely to stop. Hopefully there is a magic setting somewhere.