# Soundtraxx and there slow speed control



## Grabbem88 (Feb 24, 2012)

I am using only a nce power cab and a lot of trial and error

I have tried all the website stuff from yahoo to mrdcc and so on

Cv 25 =2 did not work for me so I'm using different maps cv25=7 been pretty good for my gp-7's and rs-1's

Cv209=35-45 has been my range

Cv210=5-8 

Cv213/214=8 on both

Cv212=120's and 150 <something isn't right here

Cv10=0 40 and 70. I can't reason with it

My goal is speed step 1-3 to cooperate with me

It's either step 3 I get movement while 1-2 just try's and stops

Now if I add cv2=1-3 I get a good start. What I have read this is a no!???

Could I get some more advice on this or maybe try somebody's

Program for say an atlas product geep or rs1 or -8

I want to see what I overlooked

Thanks art


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## NIMT (Jan 6, 2011)

The CV's that your trying to tweak are for Motor KP coefficient, Motor Ki coefficient, Motor control sample period, motor control intensity, BEMF Cutout, None of these are for speed control, and changing these #'s randomly will just lead to a multitude of issues in unpredictable control.
These CV's are usually determined by the manufacture of the model or motor in that model, and the Decoder manufactures have gotten the start or average #'s from them, tey are very hard to change these #'s without a whole lot of knowledge, equipment and insider information.

To properly set speeds and curves on any Soundtraxx decoder it's fairly simple, and very adjustable.

Before doing anything do a factory reset to get all values back in line.
Set CV 25 (Speed table selection) to 16 = (User defined)
Adjust CV's 67-95 to get the proper start and top end that you want.
Example, CV 67=0 CV 68=2 CV 69 =4 and ... up to CV 95 = 255 for high top end speed, reduce the top # to get a slower top end engine.
To adjust rate of start and stop, higher the number higher the time.
CV 3 0-255 (Acceleration rate)
CV 4 0-255 (Braking rate)


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## Grabbem88 (Feb 24, 2012)

I'm working on them right now and that -8 Amtrak you saw whines up "then" starts and crawls pretty darn slow with no jumping and bucking 

My rs1 is the way it's supposed to be wide open and going nowhere! Actually top speed is 20 but mine barely did 10 but it was a pos with a great heater so I didn't care..

Anyways there has been no random anything


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## NIMT (Jan 6, 2011)

Well that explains why I think that your other engine (Dash 8) starts and runs odd.

Well do what you think is best for you.


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## Grabbem88 (Feb 24, 2012)

I didn't program anything motor wise the first time 

And we all have different thinking so that was the whole idea of this post 

There is so many ways to run and operate a tsunami board that we are getting away from the goal here... Having fun


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## NIMT (Jan 6, 2011)

All I was trying to point out what is the best way to program the decoders to get the overall best results.


I've been programming DCC decoders for 20+ years and have run into almost every scenario over the years, on top of that I have a team of Soundtraxx engineers at my disposal to answer any question that I have had over the years on the way they intended the different CV's ability to control there decoder. :sly:
I have also run into many that feel that they have "better ways" to program decoders and I have gotten to the point where butting heads with that person just isn't worth it, so I just move on! :dunno:


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## Grabbem88 (Feb 24, 2012)

I hear ya and agree but wanted to see if anybody has tried what I did


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## irishthump (Jul 1, 2013)

Hi, Art.

I recently got a Bachmann Soundvalue F7 which uses a budget Tsunami decoder. Like you I had trouble getting good slow speed control but after a some tweaking I got it running well. Like you I adjusted the KP/KI coefficient.
I can't remember exactly what values I programmed into the CV's but this article is a great guide.

https://sites.google.com/site/markgurries/home/decoders/decoder-motor-tuning/soundtraxx


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## Northern Route (May 12, 2014)

I have some 20 year old Athearn F7s that I installed decoders in them. I set my throttle to 128 speed steps and turn it up until the motor tries to move, at that time I adjust the kick rate to get it moving as slow as possible. I use that value to for the low end of the speed curve and then set top and midrange values of the curve. It just a matter of finding that low speed operation and those old motors needs some kick to get them rolling.


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