Acceleration Rate

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Summary: The Acceleration and Deceleration of rates multifunction decoders are controlled by several Configuration Variables

Acceleration and Deceleration

The Acceleration rates are controlled using CV 3 and CV 4. These CVs are mandatory. This feature is used to simulate momentum.

Acceleration Adjustment 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.

Optional Adjustment CVs

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.

Along with CV 24, CV 23 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 (CV 24)

It is the same as CV 23, except CV 4 is acted on.

European Exception

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

Further Reading

Refer to the page on Configuration Variables and MU Consisting for more information on CVs and how these features are used.