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Stupid question: Digitrax Throttle DT402

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  • Member since
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  • From: Pa.
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Stupid question: Digitrax Throttle DT402
Posted by DigitalGriffin on Monday, November 19, 2012 12:53 PM

The display shows the throttle as a percentage (Between 0->100% throttle)  (According to the manual)

Is there a way to display the current speed step?

There's a calibration routine I want to try, and the instructions tell me to set the engine at specific speed steps for each calibration.

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

  • Member since
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  • From: Reading, PA
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Posted by rrinker on Monday, November 19, 2012 4:26 PM

 Other than carefully count the clicks, no. 128SS is actually 126, so calculate the current speed step using a percentage of 126.

 JMRI can show the exact speed step for a given loco by looking at the slot status in the command station. Or the on-screen JMRI throttle run in speed steps as well.

                 --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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  • From: SE Minnesota
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Posted by jrbernier on Tuesday, November 20, 2012 11:46 AM

  Like Randy mentioned, the Decoder Pro(JMRI) software will show the actual speed step.  I guess my question is 'why' are you concerned about the actual speed step?  In actual practice, a decoder has only two modes: 14 speed steps, and 28 speed steps.  It calculates the128 step via an internal algorithm.

  If you are speed matching two engines, what really matters is do the run at the same speed at the same throttle setting.  Even two identical models may have differences dues to friction in the drives and  the same exact settings will not produce the same result.

Jim

Modeling BNSF  and Milwaukee Road in SW Wisconsin

  • Member since
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Posted by DigitalGriffin on Tuesday, November 20, 2012 2:15 PM

Well to set up BEMF

QSI recommends starting at speed step 8

Soundtraxx, says speed step 20

I know the conversion is simple.  But it's not 1:1 as there is more then 100 speed steps.  So I guess it's either time to use the QSI programmer as command station mode, or use JMRI.

Thanks for letting me know guys.  I was hoping there would be a work around.  I guess not.  Maybe a future firmware update will solve the problem.  (Make it a cab option)

 

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

  • Member since
    July 2008
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Posted by mfm37 on Tuesday, November 20, 2012 4:40 PM

If you have the throttle set up to beep as speed is changed you will notice that every third beep there will be one extra beep before the display increases. This is how Digitrax gets the 128 speed steps on a 2 digit display.

One of the people on the Yahoo Digitrax group matches speed using a measured test loop of track and a stop watch. He has a table of scale speeds based on distance/time on the measured loop. Scale speeds are set to match the throttle display for every engine. This way every engine is running the same speed at each number on the throttle. He's N scale, but the same could be done in other scales with a little calculation.

here's a link to his speed matching web page: http://www.cuttergraphics.com/N-trak/speed_matching.htm

Martin Myers

  • Member since
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  • From: Reading, PA
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Posted by rrinker on Tuesday, November 20, 2012 5:25 PM

 Hmm, I guess I'm not so picky, but my locos all run well and creep nice and slow, and all I do is set them up to run as slow as they can on speed step 1 or 2. My motor only deocders are all TCS though, there aren't any BEMF settings, they self adjust, very well I might add. My one Tsunami runs great out of the box, as does my one QSI. 

 What's more interesting is that a mix of locos runs well together without doing and speed adjustment - The Tsunami with a TCS, and also a pair of Proto Geeps with TCS cooupled tot he Atlas Trainmaster with a QSI - they all run great together and I've changed nothing. If I set them on the layout a few feet apart, they don;t run perfectly in step, but coupled together with a train they don't jerk and buck at all.

               --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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