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Speed matching with a speed table?

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  • Member since
    July 2003
  • From: Metro East St. Louis
  • 5,743 posts
Speed matching with a speed table?
Posted by simon1966 on Friday, February 13, 2009 7:25 PM

Hi folks,

I am using Decoder Pro hooked to my Digitrax Zephyr DT400 throttle combination.

I am helping our buddy Cudaken, he lives in the next town, with a bit of programming for some of his locos. 

OK, I am somewhat adept at speed matching using the simple start, mid and top voltage setup.  However 1 of his 3 P1K F3 units does not want to play nice.  It has a very non-linear response to the throttle compared to the other 2.  It speeds up quickly in the low range, causing all sorts of problems when consisted. The first 2 I have speed matched perfectly through out the speed range.  This 3rd one I am having to fine tune using the speed table. 

The speed table for the decoder has 28 steps.  My throttle has 0-99 increments, so it is roughly 3.5 throttle stops per speed step.  Having set the top speed and the low speed I have been figuring the approximate relationship between the throttle and the 28 speed settings and have been fine tuning to get a more linear throttle response.  It is somewhat tedious, so was wondering if I am approaching this the right way?

Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Friday, February 13, 2009 9:57 PM

 If they all have the same decoders, that oddball sounds like it already had some attempt at speed matching. Try resetting the decoder and giving it another try. Don't forget CV29 has to be changed to enable a speed table - but I think DecoderPro does that for you because you have to click the check mark to even get the speed table page to open.

 You're on the right track though, there's not much else you can do but go through each speed step and adjust that step's slider so it matches the others at that same speed step. It might be easier to sue the JMRI throttle, or at least use the slot monitor to verify it's at, say, speed step 8. Run oen of theothers also at speed step 8 and then adjust the table slider in ops mode to make the oddball runt he same speed. Then advance both to speed step 9 and repeat. 28 times.

                          --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
    February 2005
  • From: Vancouver Island, BC
  • 23,330 posts
Posted by selector on Friday, February 13, 2009 11:37 PM

rrinker

 ... It might be easier to sue the JMRI throttle...

                          --Randy

 

Geez, Randy, you got the software for nothing....what more do you want?! Smile,Wink, & Grin

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, February 14, 2009 1:58 AM

 Sorry, thought I was Matt Katzer there for a second Big Smile

It's nearly 3am here, I'm using my laptop which has a way different keyboard than my desktop, and I'm still at work. That's my excuse and I'm stickign to it.

 

                            --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
    January 2001
  • From: SE Minnesota
  • 6,847 posts
Posted by jrbernier on Saturday, February 14, 2009 8:02 AM

  Those P1K F3's can vary quite a bit.  Of the 3 I have, one had completely different speed characteristics with the same type of decoder. Reset/swapping decoders did not resolve it.  In DC they would run OK.  Swapping motors/trucks finaly got a combination that resulted in 3 engines that would run the same with a basic decoder setup.

  BTW, pull that 'light board' in them and toss it.  Hard wire the trucks/motor to a decoder harness.  The electrical pickup in them varies from good to lousy.  I 'formed' the pickups and ran new wire from them.  They now run very good, with few electrical pickup issues(NWSL n/s wheels as well).

Jim Bernier

Modeling BNSF  and Milwaukee Road in SW Wisconsin

  • Member since
    July 2003
  • From: Metro East St. Louis
  • 5,743 posts
Posted by simon1966 on Saturday, February 14, 2009 8:25 AM

Thanks Randy, I already re-set the little blighter and it was not the issue.  Thanks for the little gem of suggesting the slot monitor!  I had not thought of that and  now can be sure that I am on the correct speed level.

Thanks

 

 

Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum

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