Scale Speed v Speed Steps

[cowside]

In the Railmaster manual it advises using Scale Speeds as a set-up option and states that a less good alternative is to use DCC Speed Steps (0-127). What do forum members think is best?

And following on from this, do you also normally set CV29 to 128 steps (using Hornby R8249 chip)?

[Fishmanoz]

The default in CV29 for most decoders incl the 8249 is 6 meaning 128 speed steps (2) and DC operation (4).  So there is no need to turn it on, it's almost universal these days, you have to turn it off if you don't want it.

 

RM scale speeds makes no adjustment to speed steps or speed curves, it simply limits your throttle to not exceed max scale speed and puts shunt near the bottom.  I'm pretty sure it does this by selecting appropriate speed steps for these settings.

 

To do anything like this in a decoder, you need to set the appropriate Vmax, Vmid, Vmin and/or select complex speed curves in CV29 (bit 4=16).  But none of these are supported by the very basic 8249, so scale speeds and/or good throttle control are your only options. 

[St1ngr4y]

But none of these are supported by the very basic 8249, so scale speeds and/or good throttle control are your only options. 

... or by running your trains under the control of RM programs, utilising the accelerate/decelerate commands.

Ray

[cowside]

Thank you. I had actually been turning off the 128 speed steps bit in CV29 - most of my setthings are 32 for long address and occasionally 33 if reverse direction is needed. So should I enable the 128 speed steps bit or does it make no difference??

[Chrissaf]

......................or does it make no difference??

.

If you have any locos with directional lights. The lights will not work unless 128 speed steps is enabled.

[Fishmanoz]

What I don't understand is why you'd want to turn it off and only have course control over speed when you can have fine control?

[cowside]

What was not clear whether the Railmaster sotfware when set to use scale speed ignored the speed step settings on the decoder. From the replies it seems speed steps still apply even if the Railmaster is set to scale speed. Exactly what I wanted to know since I could not find that anywhere in the documentation.