Inc Sound Module Decoder - Manual

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8.2 Throttle Response Curves & Loadable Speed Tables

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

25%

50%

75%

100%

Motor

Voltage

Applied

Speed Steps

THROTTLE RESPONSE CURVE

Default Curve

V-start, V-mid, V-max 3 Step Table Curve

28 Step Loadable 

Speed Table Curve

When using a throttle to control a locomotive, you will notice that as you

increase and decrease the speed, the loco responds to the change in throttle

settings according to the relationship between motor voltage applied and the

throttle setting. This is called the throttle response curve. Decoders are shipped

from the factory with a linear throttle response curve. This means that as you

increase the throttle setting from 0 to full speed, the loco will look like the

default curve in this diagram.

If you want to create a more realistic throttle response curve, you can set up

either a simple three step speed table or a loadable speed table.

The simple speed table involves setting three CV values. The loadable speed

table is a bit more involved with more precise results. Loadable speed tables

define the percentage of motor voltage applied at each of 28 digital speed steps.

By programming a value for each of the 28 steps, you can set up a customized

throttle response curve for each individual decoder equipped locomotive. The

shape of this curve defines the “feel” of the decoder’s throttle response.

With Digitrax FX

decoders, when the loadable speed table is active and 128

speed step information is received from the command station, the table is inter-

polated to generate 4 in-between steps to give full 128 step resolution.

You can use the 3 step method for some locos and the 28 step method for other

locos on your layout, you do not have to choose only one method or the other.