SoundTraxx DSD-150/DSX Technical Reference - Manual (Page 43)

Address Mode Direct Mode
Register Mode Ops Mode Short Form
Paged Mode Ops Mode Long Form
Digital Sound Decoder Technical Reference 43
CV 66
FORWARD TRIM
Description
Contains a value, n, between 0 and 255 that specifies a scaling factor interpreted as
N/128 by which the forward drive voltage is multiplied.
bit 7 bit 0
D7 D6 D5 D4 D3 D2 D1 D0
D0-D7: Forward Trim Scalar
The forward trim scalar allows the decoder’s overall throttle response in the forward direction to
be adjusted up or down for the purpose of matching one locomotive’s speed curve to another.
See graph below.
A trim value of 128 (0x80) yields a scaling factor of 1.0 which will have no net effect on the speed
response.
Trim values between 129 and 255 (0x81-0xFF) have the effect of increasing the motor voltage by
a factor ranging between 1.01 to 1.99.
Trim values between 1 and 127 (0x01-0x7F) will decrease the motor voltage by a factor between
0.008 and 0.99.
A trim value of 0 disables the trim scalar
computation.
This CV is used only when speed tables are
enabled (CV 29, Bit 4 = 1). Otherwise, this
CV will have no effect.
Default Value: 128 (0x80)
Related CVs: See also Reverse Trim, CV 29.
❐ ■
❐ ❐
■ ■
100%
75%
50%
25%
0%
0 14 28
CV66 = 255
CV66 = 128
CV66 = 64