Thanks to Mark Gurries for this information
BEMF/Advanced Consisting & Digitrax
Problem: Does your Digitrax Decoder stop working when in Advanced Consist Mode?
To learn more about all the different types of consisting and term confusion, go here: Consisting Information
CV57 contains two 4 bit value
Why? Digitrax decoder from the factory have BEMF control disabled when the decoder is part of an Advanced Consist. Advanced Consisting is also known as "Decoder Assisted Consisting" using the decoder's CV19 to implement it with. To be clear, is your using "Command Station based Consisting" also known as Basic/Standard consisting, this situation DOES NOT APPLY.
Digitrax command stations use Basic/Standard consisting by default, which Digitrax calls uniquely Universal Consisting, and is why this is not a problem for Digitrax users.
Why Does Digitrax Do that? Given the goal of Advanced Consisting is no different then Basic/Standard Consisting from a operations point of view, then why is advanced consisting be penalized by default unnecessarily? Other than Digitrax, who knows. Does not make any sense.
1) Stand Alone Engine: Engine runs fine at all speeds with good low speed performance. Works fine in a Basic or Standard Consist setup too. Engine speed is similar to other engines on the layout.
2) Part of Advanced Consist: Engine seems dead in consist. Will not move. Turnout up the throttle will get the engine to move but the speed does not match the other engine in the consist.
CV57 is complex CV which contains to values that are combined. In hex, they are two digits. 0xYZ Each digit, Y or Z, allows one to tuned the intensity for both normal operation and when the decoder is part of an Advanced consist independently.
The lower first digit/number controls the intensity in effect when the decoder is operating normally.
The upper second hex digit/number controls the intensity in effect when the decoder is part of an advanced consist .
For both numbers, CV57 controls the amount of intensity or speed loss as load is increased, by limiting the amount of change or compensation that the decoder is allowed to implement. Stated another way, CV57 allows you to independently controls the BEMF intensity for both normal operation and when it is part of a consist.
In decimal the range values for each digit is 0 to 15. In hex the range is 0x0 to 0xF.
DEFAULT VALUES: CV57 is set to 5 for standard operation and 0 for Advanced Consisting. In hex, CV57 = 0x05. Hence the problem.
SOLUTION: Program CV57 to enable BEMF operation in an Advanced Consist. Program CV57 so both hex digits are the same value of 5 which is 0x55 or a decimal value of 85.