Adjusting start speed

[tnolan55]

I have an Sd70mac from athearn genesisand i would like to change the speed step it starts moving at to step 1. I do not know how to do this so I would like some help.

 

[fast_ian]

"Start speed" is always zero! [Sorry - Couldn't resist ]

What you're looking to change is the start voltage - This is set in CV02, and (generally) defaults to 0.

I don't know what decoder you've got, but I'd try setting CV02=02 and see what happens - If it still doesn't move, you can increase the value of CV02 until it does (On Digitrax decoders at least it can go as high as 255!) - Beware however - Setting it too high will result in it taking off at top speed at speed step 1.....

Once you've got CV02 set, CV06 will set the mid voltage and CV05 the maximum. [Setting CV05 to ~150 slows the the top end down for me such that folk can't pretend they're at Daytona for example!]

HTH, cheers,
Ian

 

[tnolan55]

Thanks for your help and by the way, I am using a tsunami tsu-gn1000 decoder.

 

[fast_ian]

...I am using a tsunami tsu-gn1000 decoder.

Hmmm - I had a quick look at the manual and it seems only VStart (CV02) is supported - They simply don't show CV06 and CV05 in their listing.

So, I was correct about setting CV02, but if you want to go further it seems you're going to need to load a complete speed table (CV's 67 thru 94).

Got JMRI?......

Cheers,
Ian

 

[Selector]

I have a BLI J Class with a Tsunami 'heavy' in it. It was jerky at low speeds, and I had CV2 set at zero.

I have learned that with CV2 at 0, put a single speed step on your throttle with the loco clear to run forward close to level for several feet on the rails.

Enter programming on the main, to CV209, and enter a value near 30. Then enter CV210 and enter a value just a bit higher, say 40. You should find that the mechansim smooths out quite a bit. If not, go back to 209 and double the value of 30 to 60, and do the same for 210. At some point your engine's drive should smooth out. Exit, and you should have your engine moving on speed step 1. If not, add 1 or more to the value already in CV2.

It seems involved, but once you do this you will never forget both the procedure and how useful it is. Worked like a hot damn for my slightly jerky and annoying J.

 

[fast_ian]

Enter programming on the main, to CV209, and enter a value near 30. Then enter CV210 and enter a value just a bit higher, say 40. You should find that the mechansim smooths out quite a bit.

I don't have any Tsunami's, but the above prompted another look at their CV's - 209 is "Kp coefficient" and 210 "Ki coefficient".

Are these "kick start" parameter(s)? Why two?

Cheers,
Ian

 

[Selector]

I have no idea, Ian, not being a DCC guru, but they may also affect BEMF somehow. It would be a good question for the Tsunami interest group on yahoo or someplace like that.

 

[diburning]

I don't have any Tsunami's, but the above prompted another look at their CV's - 209 is "Kp coefficient" and 210 "Ki coefficient".

Are these "kick start" parameter(s)? Why two?

Cheers,
Ian

I think that's for the BackEMF settings. I don't use BackEMF (unless it's turned on by default) so I wouldn't know.

 

[tnolan55]

Okay i got it to work for the sd70 athearn genesis model. but it wont work with my Bachman spectrum with the factory equiped decoder. any suggestions on what to do?

 

[diburning]

Does your Bachmann have a tsunami or a regular non-sound decoder? The non-sound decoders are what I would consider to be "crippled" (in the sense that theres not much that you can adjust)

 

[tnolan55]

yea it is a non sound equiped decoder.

 

[bnsf971]

yea it is a non sound equiped decoder.

You can adjust cv3 and 4 so it will start out and slow down slower. I don't think CV2 is supported.

 

[Cjcrescent]

I just checked a basic Bachmann decoder on JMRI. CV 2 as well as 3&4 are supported. According to JMRI these decoders support staring voltages only, with no speed table adjustment available.

 

[fast_ian]

With apologies for the hijack....

... the above prompted another look at their CV's - 209 is "Kp coefficient" and 210 "Ki coefficient".

I have no idea, Ian, not being a DCC guru, but they may also affect BEMF somehow.

I think that's for the BackEMF settings.

So, I couldn't let that rest! They're not BEMF but "related"..

CV209 contains a value between 0 and 255 that specifies a gain factor for the proportional part of the PID motor control equation.

CV210 contains a value between 0 and 255 that specifies a gain factor for the integral part of the PID motor control equation.

CV214 contains a value between 0 and 255 that specifies a gain factor for the derivative part of the PID motor control equation.

Now, if I could find the "PID motor control equation" I'd be happy. I suspect most have gone glassy eyed by now, but I love a good equation!

Okay i got it to work for the sd70 athearn genesis model.

Did you adjust CV02? Or did you tweak it as suggested by Selector? Both?

Cheers,
Ian