R8249 setting to 14 speed steps

[jbanfie]

Hi all,

 

It's a long story but I'd like to set my new R8249 to 14 speed steps but the instructions don't tell you how - they just say the number of steps is selectable???

 

Is it as simple as setting bit 1 of CV29 to zero?

 

Thanks in advance

 

Jon

[Flashbang]

Hi

14 speed steps is virtually a non existent setting nowadays!

Use 28 as the minimum and 128 as the preferred for finest of speed control.

Some decoders cannot accept 14 as its so outdated. But the R8249 does support this setting.

Decoder

 

manufacturers are dropping support for 14 speed step mode as the DCC standards no longer require It.

 

Why?

 

14 speed Step mode creates unnecessary operator frustration when the person is not aware of the rules and programming required.

 

To

 

resolve this, the NMRA DCC standards have been change to make the old and outdaterd 14 speed steps mode from being a mandatory speed step range requirement to being optional. 28 speed step is now the minimum requirement. The goal going forward is to phase

 

out the 14 speed step option which will eliminate the need for any type of decoder speed step programming requirement.

 

But back to your question.. If you use the Hornby Select - see the manual page 21 for changing speed steps. For the Hornby Elite -

 

see the Elites manual page 20. If you use another make of DCC system then it will be dependant on how the systems manufacturer has configured the console.

[Gregd99]

I currently operate my locos in 14 step mode.

 

Why?

 

One of the things I am very interested in is computer controlled operations. My background is in software and my layout has been a fun way to learn about model rail, practice some electronic

 

skills and write some software:-) I know that this is not everyone's interest.

 

The Elite has a number of unique "features" in the implementation of the pc interface. When I investigated the interface about 3-4 years ago the features included period

 

non-performance of point and throttle commands, incorrectly formatted responses and.... always reporting a loco as operating in 14 step mode.

 

The format of throttle status messages is determined by the step-mode of the decoder. It is important that

 

these are aligned in the control software.

 

Some features might have changed in the meantime but in conversation with Hornby corrections to the interface were not high on their priority list. I expressed my concerns as the elite is bad-mouthed on a number

 

of forums due to these issues.

 

I use JMRI for control. No problem talking about this I think as it is not at all a competitor for Railmaster. Whereas Railmaster is a "shrink-wrapped" package designed to be an easy entry, with limited functionality,

 

into the world of computer control... JMRI is decidedly more in the geekosphere. It has pretty much unlimited capability but you "earn" the outcomes you achieve with a fair bit of work.

 

JMRI was adapted for the elite quirks with the exception of the

 

non response to commands. This required a fair bit (hundreds of hours) of scripting to understand, detect and resolve the issues when the occurred. Railmaster will probably have implemented the same sorts of changes although there have been threads reporting

 

non responses with Rail master as well.

 

So.... a long response but that's why I use 14 step mode.

 

[jbanfie]

OK all of that is great, but how do I programme the decoder to be in 14 step mode?

 

I need 14 step decoder operation, as I want to use an old LGB central station which only supports 14 speed steps as LGB were doing DCC back in 2001.

 

My R8249

 

comes pre-configured as 128 steps, how do I change it?

 

Cheers

[Flashbang]

Hi

You will need to read the value set currently in CV29, then deduct 2 from whatever is read and enter that new value. e.g. read 6 then enter 4 or read 38 so enter 36. Note this will turn off 28 and 128 speed step settings in the decoder.

 

The

 

reason you need to read CV29 first is to see what value is already being used. It will alter depending on whether the decoder is set to 2 or 4 digit addressing, has dc turned on or off and what the normal direction of travel is etc.

Its impossible to just

 

enter a value without knowing what value is in CV29 first. Warning altering CV29 'blind' will result in some very unusual loco motor operation or at worse a total failure to operate!

 

This simple CV29 calculator chart shows the permutations....http://www.2mm.org.uk/articles/cv29%20calculator.htm