# Tsunami V start modification



## Peter (Jan 31, 2012)

I just installed TSU 1000 and notice that the factory default V start is set too high and I can’t lower it with Vstart settings or speed curve both set to 0
I love the sound quality but the motor control at low speed is at list challenging. Would appreciate any help.
Peter


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## NIMT (Jan 6, 2011)

Which CV# are you programing?


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## Peter (Jan 31, 2012)

I’m using Decoder Pro software for programming - in motor control V start setting which is CV2 - set at 0 and I tried speed tables both pre loaded and user defined. I set the first three bars to 0 and still can't reduce starting voltage.


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## NIMT (Jan 6, 2011)

Did you set both of these settings? (orange highlights)


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## Peter (Jan 31, 2012)

yest and in differnt curves as well


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## NIMT (Jan 6, 2011)

Give me a copy of the decoder settings. You can do that threw the roster file. and I can look it over and see if your missing anything.


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## Peter (Jan 31, 2012)

Sean I don’t think that anything is wrong with the decoder settings. To start with I had this same model running on $20 Digitrax decoder for tests and I was able to control the v start very nicely with basic speed curve adjustment to the point where the model will not move all the way to speed step 6. In my opinion the tsunami decoders has higher V start value factory set. I tested two other models from my collection equipped with tsunami and notice this same. I can’t reduce v start voltage any lower and the models are starting moving from speed step1. As per conversation with tech support there is a way of changing this setting but according to them it will required changes to hyper drive control and I don’t have the procedure.


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## NIMT (Jan 6, 2011)

What DCC controller are you using?


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## NIMT (Jan 6, 2011)

Your going to have to tweak the motor values.


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## Peter (Jan 31, 2012)

yes.... welllllll  Kp and Ki only or all of them any suggestions where to start ?
....I'm using Digitrax system.


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## NIMT (Jan 6, 2011)

You will have to play with the values to match up to the motors needs.. I would play with the numbers just a little at a time. I'm sorry I can't give you exact answers but each motor is different and each one reacts differently to the change in the values. Sometimes you can get lucky and listen to what the sound is doing and that will give you hints to which way you need to tweak it.


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## cabledawg (Nov 30, 2010)

Hey Sean, can you explain what each of those functions do? I have a couple locos that need to be tweaked as well, but didnt feel compelled to to mess with anything other than the step values.


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## Peter (Jan 31, 2012)

cabledawg said:


> Hey Sean, can you explain what each of those functions do? I have a couple locos that need to be tweaked as well, but didnt feel compelled to to mess with anything other than the step values.


yes! ... same thing here i have ruff idea but would love to know more about it.
Thx for your help !


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## NIMT (Jan 6, 2011)

Ok this has me going way over my pay grade to try and explain!
The Kp (perpotional gain) and Ki (integral gain) are used in a PID formula.
If I told you how exactly it works I'd have to kill ya...Oh wait...Strike that... I'll Let Wiki try and explain it better than I ever could.
WIKI HERE:

Motor Kp Coefficient, Motor Ki Coefficient, Motor control Intesity, Motor control sample period, Motor control sample aperture time are all factors in the puzzle.

Motor recovery speed is a value or precentage at which the recovery of speed after a power interuption happens

*CV 118 *
*Motor Recovery Speed *
*Description *
This CV adjusts the motor recovery speed for momentary interruptions during power glitches. 
0 = Disabled 
1-127 = Absolute Limiting: When set between 1 and 127, the decoder will limit the recovery speed to the motor to the corresponding speed step. 
128 = Disabled 
129-255 = Proportional Limiting: When set between 129 and 255 the decoder will limit the power to the motor after a power loss to a percentage as shown below: 
*(CV 118 - 128 ) *
*Percentage = ----------------------- *
*127 *
*Default Value: *204 (60%) 





*Advanced Motor Control Features *
*CV 209 Kp Coefficient *
*Bits 0-7: *D07 sets the Kp Coefficient 
The CV contains a value between 0 and 255 that specifies a gain factor for the proportional part of the PID motor control equation. 
*Default Value: *25


*CV 210 Ki Coefficient *
*Bits 0-7: *D07 sets the Ki Coefficient The CV contains a value between 0 and 255 that specifies a gain factor for the integral part of the PID motor control equation.
*Default Value: *20

*CV 212 Motor Control Intensity *
*Bits 0-7: *D07 sets the Motor Control Intensity The CV contains a value between 0 and 255, interpreted as n/32 that is fed back from the control loop.
*Default Value: *255

*CV 213 Motor Control Sample Period *
*Bits 0-7: *D07 sets the Motor Control Sample Period The CV contains a value between 0 and 31, that specifies the time period in mS (milliseconds) between measurements.
*Default Value: *15

*CV 214 Motor Control Sample Aperture Time *
*Bits 0-7: *D07 sets the Motor Control Sample Aperture Time The CV contains a value between 0 and 255 that specifies a gain factor for the derivative part of the PID motor control equation.
*Default Value: *15

There is another variable that is very useful in speed matching engines.
 
*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. 
*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 
*Related CVs: *See also Reverse Trim CV 95, CV 29, CV 25.


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## NIMT (Jan 6, 2011)

Peter,
Also when setting the values in the decoder also set the Analog values too, they can effect the digital values and their thresholds.


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## Peter (Jan 31, 2012)

lokks like a solid plan for Friday night anywhere between 10pm and 4am. I will report progress accordingly


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## Peter (Jan 31, 2012)

Done! Thank you Sean. I ended playing with Kp and Ki only. increased CV209 to 30 from 25 and CV210 drop all the way to 1 from 20. The engine will not even start moving in speed step 1 starts crawling in step 3 while before in step 1 would just immediately start moving. All I need to do now i just play with the speed curve smooth the low end.


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## NIMT (Jan 6, 2011)

:thumbsup::thumbsup: Peter!!
Not many have the courage to venture into the land of the unknown (or the hidden DCC CV's)! I've been doing DCC installs for years and there is almost no limits to what you can pull off with the right DCC Decoder!
Just remember as you change the speed curve you might have to go back and tweak the Kp and Ki values again just to get the fine fune down!


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## Peter (Jan 31, 2012)

thx ...now I also have two overland brass CSX engines from late 90's production run. I was planning to install the TSU's in both of them but I also know that the brass models can be challenging to convert to DCC due to different types of motors. Would you recommend starting with different decoder brand?


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## NIMT (Jan 6, 2011)

Now I think brass engines are easy to convert.
If your going to do sound I would stay with the Tsunami's!
If your doing strait DCC then NCE D13SR is the way to go!
Brass normally will have can motors that can be isolated very easily, just remember to remove the capacitor off of the motor.
I start with making sure it's in good running condition in DC before the transition to DCC.
Lighting can sometimes be a challange, I use all LED's when I convert them to DCC, it lowers the possibility of having to go back in and replace a burned out lamp.
Sound in Brass can either be easy or really hard to obtain good results, just remeber that the frame and body tends to resonate sound, a speaker baffle is a must in those!


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## Peter (Jan 31, 2012)

Have you had a chance to work with the new QSI Titan decoder?


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## NIMT (Jan 6, 2011)

Just a little, I don't have all the hardware to be able to tweak them around as much as I like to. They are a nice sound decoder, but I think that the Soundtraxx Tsunami line is right there with them for cheaper and easier install too, Finding room for one speaker can be tough enough enough in most units but two can give you a heart attack!


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