27 speedsteps?

[ronbram]

I have recently bought a  Hamo (=2-rail DC Marklin) DB 86 620 steam loco with digitally controlled couplers. The loco is fitted with a very old (greyer then me) factory fitted Marklin/Lenz dcc decoder. I can use it with my twin center, when I set it to use dcc 27 speedsteps. I can run it with the elite, but no function is working (light, telex couplers, nothing). I tried 14, 27 and 128 speedstep setting in the elite, no effect. A 27 speedstep option is not part of the elite firmware or does anyone have a trick to run this loco in 27 speedstep mode?

[96RAF]

Hi Ron - nice to jear from you again.

Did Marklin not use a special type of DCC. I seem to remember some decoders that had separate settings for DCC - Marklin - something else. Maybe American MBH/MBG/MFX or similar.

 

John (yelrow) has one of these big American MFX ? locos and that was awkward to set up to run on pure DCC.

 

Maybe the old decoder just needs a bit more tweaking for DCC using your faithfull Twin-Centre

 

Edit - this Wiki tells a good story about the in er working of Marklin and its system

https://en.m.wikipedia.org/wiki/Märklin_Digital

I also found this reference on the Marklin users net forum

 

/media/tinymce_upload/9ecaeaf0e869578fb68b7205ad81ad02.png

[2e0dtoeric]

Unless I'm picking up the soldering iron by the hot end - don't 'speed-steps' ONLY affect the motor behaviour, and not any of the other functions?

ie - (a very crude example) a two step control would give either off or full power - a three step off-half-full?

So the more speed steps, the smaller the increments - over the same range of off to full - giving a smoother response?

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It is more likely that the Marklin decoder is not recognizing the data commands for the auxiliary functions - due to it being pre modern standards.

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It would be interesting to couple up the 'twin centre' (not familiar with that controller) and an oscilloscope, to see what wave-form is being generated, and compare that to the output of the Elite.

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Just a thought - is the o/p confusing 'speed-steps' with 'frame-rate' - the number of data signals per time period?

[96RAF]

I remember now the other (American) loco was MTH not all those other acronyms I tried to guess.

 

You are right Eric about speed steps but it is the way these multi-standard decoders and controllers can be set up that invokes this odd 27 step regime which brings in other control factors.

The Wiki I linked to explains it better than I can.

[Chrissaf]

Then there is the known quirk example where in the majority of cases on normal DCC decoders, directional lighting doesn't function unless 'speed steps' are set at 128 .... why this so ... no idea.

[ronbram]

From what I can remember from my Rocrail programming days, some DCC formats (depending on how many speedsteps) use a combined direction/function/speed(?) command message , while tother formats don't. This is the reason that when using the wrong speedstep setting, the headlights (F0) can react strangely. I got a tip on how to program the decoder to 28 speedstep setting, job for tonight.

[2e0dtoeric]

Some things don't change!  😎  the expense of upgrading an existing layout was considerable.