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Hi Peter
If you're using two identical mechanisms with two identical decoders I wouldn't have thought you'd need to make any adjustments to the CVs. Unless you mean to reduce the maximum speed (set CV5 to 32?) because they are shunters but you can simply turn on Function 3 to do that (reduce speed for shunting) . In fact the decoder has no speed curve setting capability other than that, anyway. The only other adjustment might be for the Back EMF.
Are you having some trouble matching their speeds?
 

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DT
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This is an extract of the Hornby Class 08 DCC installation that we did.
We debated the top speed (based on a maximum prototype speed of 27.5mph) and after
some experimentation we agreed that 100 seemed realistic enough at
the top speed for the loco. The mid point was set to 50 giving the
speed curve a straight line shape.
DCC CV Settings
for the Class 08/09 Locomotive
CV112Address (The loco
number)
CV21Minimum Speed (V Min at
step 1)
CV34Acceleration delay
(0-15)
CV44Brake Delay (0-15)
CV5100Max speed (V High)
CV650Acceleration Curve (V
Mid)
CV9216PWM frequency (69Hz)
CV293Decoder Configuration
CV490Decoder specific values
CV5020Decoder regulation

The rest of the CV's are left
untouched (factory default).
 

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Chief mouser
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11,775 Posts
Top speed for the class 13 was only 20 mph. Wasn't it the 09 that had the top speed of 27 mph?

Regards

John
 

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Doug,
What decoder were you using? Most of the Bachman 3 function decoder's CVs only go up to 63 (address goes up to 127) and there's no Vmid setting (CV6) nor CV9, 49 and 50 either.

However assuming that your CV5 is 100 out of 255 then the equivalent for the Bachman decoder would be CV5 = 24 & I guess we assume the speed curve is always linear.

what are the max values of CV 3 & 4 on your decoder? (ie is that what 0-15 means?)
 

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DT
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Yes, I suppose it does depend on the decoder. Originally there was an Arnold 81201 decoder in there - that had those funny limits.

I now have a Hornby R8215 decoder and it works just as well with no max speed setting and no Vmid either.

Without worrying too much on specific settings of any particular decoder, the aim is to keep the top speed down and to make the starts and stops slow and gradual. You don't want it to lurch off at any speed setting. Play around with acceleration delay and braking delay.
 
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