Acceleration Rate

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The Acceleration rates are controlled using CV3 and CV4. These CVs are mandatory. This feature is used to simulate momentum.

Acceleration and Deceleration Adjustment are optional features defined in the NMRA DCC Standard for Configuration Variables. They are defined with CVs 23 and 24.

CV 3 and 4

The contents of these CVs are multiplied by 0.896 then divided by the number of speed steps to determine the rate of acceleration or braking. A value of zero disables the feature.


Acceleration Adjustment

CV 23

This CV contains additional acceleration rate data that is added to or subtracted from the value contained in CV 3. It is determined by (CV 23)*0.896/number of speed steps in use.

This CV, along with CV24, is used to fine tune the momentum features set in CVs 3 and 4. These come into play when multiple unit consists are assembled.

The result is a 7 bit number, the eighth bit is the sign.

Deceleration / Braking

It is the same as CV23, except CV 4 is acted on.

European Exception

Decoders manufactured by European companies use a different factor for calculating the acceleration rates.