CV29?

[AceinOz]

I see frequent reference to CV29 in regard to how a loco runs (slow/stuttering etc). What is CV29 and what should it be set to? Apologies in advance if this has already been covered - happy to be directed to the appropriate post.

[Rog RJ]

CV 29 controls a number of things including the default loco direction, the number of speed steps, whether a 2 digit or 4 digit loco address is being used. Most of these actions are set automatically with modern controllers and you don't need to worry about them.

Stuttering is very unlikely to be affected by CV 29.

There is a CV 29 calculator here http://www.2mm.org.uk/articles/cv29%20calculator.htm that may help you understand what it does.

[Chrissaf]

I'm with Rog(RJ), CV29 has no impact on slow / stuttering issues. The link he has given you to the online CV29 calculator also provides a detailed description of CV29 and its function and is worth visiting for that reason alone.

In terms of what it should be set to, it really does depend upon what you want to do as described on the linked page. Most manufacturers default to a value of 6 for CV29, and this value suits most DCC scenarios. When configuring a Long DCC Address (one between 128 and 9999) then most controllers will amend the CV29 value automatically to support the long address without any need for the user to change CV29 manually.

In principle there are only two reasons for manually looking at the CV29 value. To change the direction the loco travels if the motor was been wired the wrong way round and to try fixing directional lighting that does not work.

[Fishmanoz]

The most usual cause of stuttering covered here is due to TTS motor algorithm set at CV150. It comes default as 0 but stuttering is often cured by setting it to 1. Then second and third order adjustments can be done if more refinement needed (very often not needed from what we see here) with CVs 151-154, a different pair used for each CV150 setting.

Full coverage of this topic can be found in a couple of other threads.