Digitrax BEMF Advance Consisting

Digitrax Decoders

Digitrax decoders use CV57 to control Both the BEMF intensity in both normal mode and in Advanced Consisting mode.  When CV57 has Advanced Consisting BEMF support turned off, there is a big drop off in speed and performance when the engines becomes part of the consist.  Stated another way, the engine may run by itself just fine but hardly moves when it is part of an Advanced Consist.

Two Solutions:

1) Turn off ALL BEMF.  Simple done by setting CV57 = 0.  That's it!  The down side is you will have to retune you decoder speeds in normal mode for the decoder will look like it died.

2) Turn BEMF on in Advance Consisting mode.


CV57 BEMF Intensity Value Range

CV57's  Intensity range for both normal and advance consisting mode is 0 to 15 (decimal) where:  
00 = Off  
15 = Fully On (Max) 
05 = Default value.


Determining the CV57 Value in Advanced Consist mode.

This section assumes you wish to keep BEMF on in both normal and Advanced Consist mode.  To determine the value of CV57, you must answer two questions.

1) What BEMF intensity do I want when using it normally.
2) What BEMF intensity do I wand when part of an advanced consist.

Typically one wants LESS BEMF intensity in Consist Mode than normal mode but NOT a zero value.  Try cutting the normal value in half and round down are required as the value for the consist mode.  Experiment as required.


Calculating the value of CV57 in decimal

CV57 is complex CV in that it controls two independent setting using a single CV.  Hence the CV57 value must combine both values into a single number.

Vn = Decimal Value for normal operation.
Vc = Decimal Value for consist operation.  This value is multiplied by 16 in the calculation below.

CV57 = Vn + (16 x Vc)

Example:  Vn = 5 and Vc = 2

CV57 = 5 + (16 x 2) = 5 + 32 = 37

Note: 255 = maximum total CV value.