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  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, April 28, 2012 12:44 PM

 If no CV6 listed, then the decoder doesn;t support CV6 for mid speed. Which one are you programming, the Tsunami? Tsunamis do not have CV6 so if you need finer speed matching (remember, it doesn;t have to be PERFECT, just relatively close. Just because you CAN fiddle with CVs enough to make two decoders in two different locos be perfectly in lockstep so that they cna circle the layotu for hours at any speed step and never get closer or futher apart doesn;t mean you HAVE to. Close is good enough and will not hurt the loco in any way) with a Tsunami you have to use speed tables. MRC, they've been all over the palce with what they support and what they don't, so it depends on the particular decoder. Most any brand of motor only decoders has full support for CV2, 5, and 6 (start, max, and mid speed, in that order - yes, mid comes AFTER top, it was a later add-on to the NMRA specs) which is generally all you ever need to adjust to get any two locos running reasonably close to one another.

                               --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 2012
  • From: Moscow, Ar
  • 91 posts
Posted by DGX GP 38 on Saturday, April 28, 2012 11:00 AM

jrbernier, I am looking over the decoder manual....see the CV's that you mention with the exception of CV 6. The list is 1-5 then jumps to 7. Maybe it will show up when the loco is on programming track. Thank you for the input.

Bryan B.

  • Member since
    January 2001
  • From: SE Minnesota
  • 6,847 posts
Posted by jrbernier on Saturday, April 28, 2012 3:48 AM

  Do not confuse BEMF with acceleration/deceleration CV's.  Not sure what is in you 1616 manual(I could not find it on-line),but I have the 1906 'Genset' manual in front of me.  BEMF load controls can be adjusted by CV113 & CV114 - MRC says do not adjust them if you are not good at 'Rocket Science'!  the BEMF 'intensity' control is CV124. and what this will give you is a sort of 'cruise control' - the speed of the engine will not change as you go up and down grades.  While this sounds 'cool', programming in  lot of BEMF will result in consisted locomotive fighting each other.  The default value of CV124 is 160(out of a range of 0-255).

Acceleration/Deceleration is controlled by CV3 & CV4 - I think this is what you are looking for.  This will slow down the start up as you open the throttle, and allow the engine to 'coast' to a stop when you close the throttle.

  Before adjusting the above CV's, you need to set the following:

  • CV5 - Top voltage/speed
  • CV2 - Start voltage - adjust this so that the engine starts to move at speed step one.
  • CV6 - this sets the speed table curve - The default is linear(0).  Changing it to a value of 1 will give you a slow increase.  This may be all you need.

Now you can play with the accelerate/decelerate CV's.  This stuff is order specific, and adjusting some CV's will affect others that you have just adjusted if you do this 'out of order'.  Also, break in the engine and let it run for 15-20 minutes so that it 'warms up'.  This makes a big difference when speed matching engines and adjusting CV's!

Jim

Modeling BNSF  and Milwaukee Road in SW Wisconsin

  • Member since
    February 2012
  • From: Moscow, Ar
  • 91 posts
Posted by DGX GP 38 on Friday, April 27, 2012 6:41 PM

Thanks Mr. Beasley. This is all new to me and not sure what will work and what will not. One more question for you if you please... I have one loco running a MRC sound decoder #1616 EMD 567. The instructions mention "back emf" ? I would like to adjust the acceleration / momentum curves so that the loco will creep along a bit longer when first start rolling. At #1 throttle setting it seems to run ok but gains speed quickly above #1. Is this the area where I need to adjust the CV setting? 

Bryan B.

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,483 posts
Posted by MisterBeasley on Friday, April 27, 2012 1:52 PM

No, you can mix-and-match most locomotive brands and decoder brands.  And a Zephyr should be able to do this just fine.

It's best, though, if the engines are "tuned" to run at the same speed.  This is called "speed matching" and involves setting a few CVs in each of the decoders.  If you use the search function over to the right (Search Our Community) and put in "speed matching," you'll probably find a number of explanations of what it is and how to do it.

Explaining it, by the way, is a lot more complicated than actually doing it.

It takes an iron man to play with a toy iron horse. 

  • Member since
    February 2012
  • From: Moscow, Ar
  • 91 posts
consist question
Posted by DGX GP 38 on Friday, April 27, 2012 12:35 PM

When running a consist, do the loco's need to run the same type / brand decoder? I'm running a digitrax dcc zephyr controller. Can this be a problem for matching speed, functions etc..?

Bryan B.

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