Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

DCC F7A and F7B do not operate at he same speed?

1607 views
9 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    January 2008
  • From: Long Beach CA
  • 13 posts
DCC F7A and F7B do not operate at he same speed?
Posted by Greazback on Monday, November 19, 2012 11:57 AM

Hello,

I have a Kato DCC N scale F7A and F7B unit. The F7A unit seems much faster and has to drag the B unit around the track. How can i correct this?

 

Thank you,

 

  • Member since
    March 2007
  • From: South Carolina
  • 1,719 posts
Posted by Train Modeler on Monday, November 19, 2012 12:18 PM

Through speed matching.  I use JMRI software so that it is very easy.   Seperate the locos and watch/time them going around a loop and adjust the speed table of the faster one so that it slows down to match the slower one.   Many articles written on the subject.

Richard

  • Member since
    December 2004
  • From: Pa.
  • 3,361 posts
Posted by DigitalGriffin on Tuesday, November 20, 2012 10:50 AM

Question #1:

Do you know what model decoders you have installed in your Kato's?

Question #2:

Do you know how to read values from a decoder on the programming track?

Don - Specializing in layout DC->DCC conversions

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

  • Member since
    January 2008
  • From: Long Beach CA
  • 13 posts
Posted by Greazback on Thursday, November 22, 2012 8:29 AM

Question #1:

Do you know what model decoders you have installed in your Kato's?

Digitrax DN163K0b

Do you know how to read values from a decoder on the programming track?

Pretty new to this so not really!

I am using a NCE Power Cab

Thank you,

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Thursday, November 22, 2012 9:19 AM

I have the Power Cab. The manual shows you how to do this. It worked for me.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, November 22, 2012 10:29 PM

 First things first, reset both decoders to make sure they are set the same. Program CV8 to 8 (don;t worry, it will NOT read back 8). DO NOT use the 'decoder reset' option from the PowerCab menu - that is ONLY for NCE brand decoders.

 Next, by default, Digitrax decoders will turn off BEMF when consisted, so if you are consisting them, there is probably no BEMF. If you simply set them to the same address, then it is using BEMF, at least they will after a reset.

 If they are both of the same vintage, ie one isn;t from a run 10 years ago and one brand new, they should be very close mechanically. If one had a lto of runnign time and the other doesn't, I would recommend givng the newer one a good break in first. Check the usual stuff - no grease, to way too much grease, etc. It's unusual for two locos of the same make and same vintage, with the exact same decoders, to be so far off that one literally is dragging the other. They may not run perfectly together without some tweaking, but if the one is actually dragging the other, something's up.

 If they work well using the same address (meaning, they will be using BEMF), you can set the decoders to use BEMF when in consist by setting CV57 to 102. If you want BEMF off at all times, set CV57 to 0. Unlike some who will probbaly post when they see me recommendeing BEMF< I have no issues running locos with BEMF in consist, they do not fight one another like some report. It's been a while since I used a Digitrax decoder with BEMF though, mine are almost all TCS, and running locos witht he BEMF turned on together results in smooth running. Two or three of the same brand loco, I haven't had to adjust a thing, no speed tables or anything.

               --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 2008
  • From: Long Beach CA
  • 13 posts
Posted by Greazback on Friday, November 23, 2012 8:38 AM

Randy,

 

Thank you for the help!

  • Member since
    March 2010
  • From: Sherwood Park, Alberta, Canada
  • 252 posts
Posted by CNR378 on Saturday, November 24, 2012 8:55 AM

rrinker

  If they work well using the same address (meaning, they will be using BEMF), you can set the decoders to use BEMF when in consist by setting CV57 to 102. If you want BEMF off at all times, set CV57 to 0. Unlike some who will probbaly post when they see me recommendeing BEMF< I have no issues running locos with BEMF in consist, they do not fight one another like some report. It's been a while since I used a Digitrax decoder with BEMF though, mine are almost all TCS, and running locos witht he BEMF turned on together results in smooth running. Two or three of the same brand loco, I haven't had to adjust a thing, no speed tables or anything.

               --Randy

 

Randy,

How did you come up with 102 for CV57?  From what I have read that puts more intense  BEMF when in advanced consist than for normal operation (6.5 versus 2).

These pages suggests 85 for equal BEMF for both

https://sites.google.com/site/markgurries/home/technical-discussions/consisting-information/bemf-consisting/digitrax

https://sites.google.com/site/markgurries/home/decoders/decoder-motor-tuning/digitrax

Peter

  • Member since
    March 2010
  • From: Sherwood Park, Alberta, Canada
  • 252 posts
Posted by CNR378 on Saturday, November 24, 2012 10:38 AM

CNR378

rrinker

  If they work well using the same address (meaning, they will be using BEMF), you can set the decoders to use BEMF when in consist by setting CV57 to 102. If you want BEMF off at all times, set CV57 to 0. Unlike some who will probbaly post when they see me recommendeing BEMF< I have no issues running locos with BEMF in consist, they do not fight one another like some report. It's been a while since I used a Digitrax decoder with BEMF though, mine are almost all TCS, and running locos witht he BEMF turned on together results in smooth running. Two or three of the same brand loco, I haven't had to adjust a thing, no speed tables or anything.

               --Randy

 

Randy,

How did you come up with 102 for CV57?  From what I have read that puts more intense  BEMF when in advanced consist than for normal operation (6.5 versus 2).

These pages suggests 85 for equal BEMF for both

https://sites.google.com/site/markgurries/home/technical-discussions/consisting-information/bemf-consisting/digitrax

https://sites.google.com/site/markgurries/home/decoders/decoder-motor-tuning/digitrax

Peter

Never mind I rechecked using JMRI and 102 gives 6 and 6 (actually 6.5 and 6). The 85 I quoted gives 5 and 5.

Peter

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, November 24, 2012 11:10 AM

 Yeah they changed the manual and in one palce is says teh default is 6, another syas they ship with 0 (that was never true when I used Digitrax decoders before), and another spot sayy 5. Back when I still bothered to use them, they came set at 6, so I went with x66 hex or 102. Mainly because I didn;t fee llike typing out a longer explanation of checking the current value and making the first digit the same and converting to decimal. Except I just did. LOL.

           --Randy

 


Modeling the Reading Railroad in the 1950's

 

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

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!