Re: Changing normal direction.


That is not accurate (and it is a common misconception).  The direction bit (CV29, bit 0) is the direction bit, but not just for the motor but for the entire model. It not only reverses the motor direction (relative to the forward/reverse commands from the DCC throttle) but also reverses the headlights (F0F and F0R).

For example a GP38-2 was generally ran with the short hood forward and the decoders installed in those locos are set up to have the short hood face forrward when the command station (DCC throttle) is set to run forward.  But few roads ran these locos with the long hood facing forward. This is when you use CV29 bit 0 to change the forward direction of the loco. Now when the command station (DCC throttle) is set to run forward, that loco's motor will run it in the long hood's direction and the headlight on the long hood will illuminate.

If a model has a backwards-wired motor, flipping the direction bit will make the loco travel in the correct direction but the headlights will be lit on the wrong end.  The only way to fix this problem is to flip the motor leads.

The chart on DCC Wiki shows the definition.  See


---In QSIndustries@..., <kjlovesya@...> wrote :

Hi Mark,

  Bob is correct.   A little more info:  CV 29 bit 0 will change motor direction (bit 0 has a 'weight' of 1) - which means you add 1 to whatever value is already in the CV.

  QSI Version 7 and above can 'speak' the values of CVs, using CV 64, while Programming On the Main (POM).

e,g,  You can easily find out what value is in CV29.  

Simply POM   CV 64 = 29

The decoder will say, "CV Two Nine equals _ ."

Now you simply add 1 to whatever number it spoke.   The result should be a change in direction. 


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