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!

Loco hesitation? Solved

2857 views
16 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    December 2005
  • From: County Schuylkill
  • 484 posts
Loco hesitation? Solved
Posted by jblackwelljr on Friday, March 7, 2008 1:46 PM

I'm using a Digitrax Zephyr on my pretend layout (4x8, oval within an oval).  I only run my Stewart FT on the inner oval because it doesn't squawk at the 18" radius.  I don't have additional throttles , so I "toggle" between locos when running both loops.  Whenever I toggle back to the Stewart (NCE/ENM D12IP decoder), it hesitates, then resumes at whatever speed the throttle is set to.  Is this hesitation normal?  It happens regardless of the throttle setting.

This isn't an earth-shattering problem, but annoying.  However, it did help me find a bad coupler - every time this happened, the same car uncoupled from the rest of the train.  The first time I didn't notice and killed the guy standing on the back of the caboose on the next roundy-round. 
Jim "He'll regret it to his dyin day, if ever he lives that long." - Squire Danaher, The Quiet Man
  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Saturday, March 8, 2008 8:46 AM

I don't have a Digitrax Zephyr, but your problem sounds to me like a command station problem in switching from one locomotive to the other, more than a decoder problem.

I use the NCE PowerPro Wireless at home and at the club and when we switch from one locomotive to another on any one of the throttles, there's no hesitation at all, regardless of the decoder type or manufacturer.

  • Member since
    February 2008
  • 416 posts
Posted by UpNorth on Saturday, March 8, 2008 9:10 AM
Please define your use of "toggle".  I tried it on mine and toggling LOCO does not cause momentaty hesitation.  You sound as if you are toggling between loops, I assume by this you mean thru a DPDT switch.  That could be your issue.
  • Member since
    December 2005
  • From: County Schuylkill
  • 484 posts
Posted by jblackwelljr on Saturday, March 8, 2008 10:25 AM
 cacole wrote:

I don't have a Digitrax Zephyr, but your problem sounds to me like a command station problem in switching from one locomotive to the other, more than a decoder problem.

If it is the command station, it doesn't do it with any other loco.  I guess it could be the way it's communicating with that particular decoder. It's the only one of it's kind on my roster, made by NCE for Empire Northern Models.

Jim "He'll regret it to his dyin day, if ever he lives that long." - Squire Danaher, The Quiet Man
  • Member since
    December 2005
  • From: County Schuylkill
  • 484 posts
Posted by jblackwelljr on Saturday, March 8, 2008 10:30 AM

 UpNorth wrote:
Please define your use of "toggle".  I tried it on mine and toggling LOCO does not cause momentaty hesitation.  You sound as if you are toggling between loops, I assume by this you mean thru a DPDT switch.  That could be your issue.

By toggling, I simply mean selecting an alternate loco once one is already running - using the loco-address-loco sequence on the command station. I understand that if the throttle is set lower than the FT's current speed, it will slow down, but that's not the issue. It actually stops momentarily and then continues.  It's the only loco that does that on my layout.

Jim "He'll regret it to his dyin day, if ever he lives that long." - Squire Danaher, The Quiet Man
  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Saturday, March 8, 2008 10:35 AM
Another thing to check is the programming of the decoder -- insure that it is set for 28/128 speed step in its configuration and not 14 speed step.  This may require reprogramming of the decoder's CV 29.  The wrong value may be in this CV.
  • Member since
    February 2008
  • 416 posts
Posted by UpNorth on Saturday, March 8, 2008 12:55 PM
Would it simply not function if the stepping were mis-matched  ?
  • Member since
    July 2006
  • From: Vail, AZ
  • 1,943 posts
Posted by Vail and Southwestern RR on Saturday, March 8, 2008 2:34 PM

Here is a theory, I'm not really proud of it, and I don't know the NCE decoder, so I might be all wet!

I believe that most decoders will stop the loco if they don't see a packet for them within a certain time.  So, what if when the Zephyr throttle is "reattached" to teh loco there's a gap between the packets that were being sent out while the system was "coasting" and when the throttle takes over?  I think there is a CV to set this timeout, at least in some decoders.  So tht might explain why this oe behaves differently from all of your others.

Again, it is just a theory, but it sort of fits the fact.  I'd look at the decoder manual, and see if there is such a timeout that can be adjusted.

Jeff But it's a dry heat!

  • Member since
    December 2005
  • From: County Schuylkill
  • 484 posts
Posted by jblackwelljr on Sunday, March 9, 2008 10:22 AM

I've checked CV29 - the value is "38" - I don't know what that means.  This was the first decoder I bought a few years ago so if there was a manual with it, I know I put it in a place where I would be able to find it - that's why I can't find it. 

Anyway, I'm going to call Empire Northern Models this week and see if he can shed any light on this. Thanks all for your ideas - I'll follow up if I get a resolution - or maybe I'll just put a sound decoder in the loco like I've been wanting to for a while.

Jim "He'll regret it to his dyin day, if ever he lives that long." - Squire Danaher, The Quiet Man
  • Member since
    February 2008
  • 416 posts
Posted by UpNorth on Sunday, March 9, 2008 6:03 PM

CV29 = 38 is

normal direction of travel,

28/128 step,

DC conversion active,

Using Vstart,

Using a 4 digit add.

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Sunday, March 9, 2008 10:02 PM

CV 29 = 38 may be the problem.  Reset it to 34.  Using VStart is possibly what is causing the hesitation.  This will also turn off DC operation mode, which will help avoid the hesitation because the decoder won't be trying to determine if it should run on DC block control..

 

  • Member since
    December 2005
  • From: County Schuylkill
  • 484 posts
Posted by jblackwelljr on Monday, March 10, 2008 6:29 PM
 cacole wrote:

CV 29 = 38 may be the problem.  Reset it to 34.  Using VStart is possibly what is causing the hesitation.  This will also turn off DC operation mode, which will help avoid the hesitation because the decoder won't be trying to determine if it should run on DC block control..

 

Cacole, you're a genius!  I changed CV29's value to 34 - hesitation gone.  Thank you. 

Jim "He'll regret it to his dyin day, if ever he lives that long." - Squire Danaher, The Quiet Man
  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Monday, March 10, 2008 7:24 PM

You're welcome.  I'm glad to hear that my advice helped.  I don't know how many times I have ran into cases where a wrong value in CV29 has messed up a decoder's performance or caused weird behavior.

 

 

  • Member since
    January 2002
  • From: Portland, OR
  • 3,119 posts
Posted by jfugate on Thursday, March 13, 2008 7:35 PM

I've found all kinds of wierd decoder behavior tied to having the DC conversion feature ON in CV29.

Always, always, ALWAYS turn DC conversion OFF in CV29 when you are first setting up the decoder. You will get much more consistent performance from the decoder.

If you need to run the loco on a DC layout, set DC conversion ON in CV29 as the last thing you do just before you remove the loco from your DCC layout. Then when you return the loco to your DCC layout, the first thing you need to do is set DC conversion back OFF!

This is one of those little DCC expert secrets that will make your DCC locos run much better and exhibit less odd behavior.

Joe Fugate Modeling the 1980s SP Siskiyou Line in southern Oregon

  • Member since
    December 2005
  • From: County Schuylkill
  • 484 posts
Posted by jblackwelljr on Thursday, March 13, 2008 8:24 PM

It just occurred to me that I posted a problem with this same loco a few months ago - when I turned on the Digitrax Zephyr, it took off without even being selected and the throttle was set to zero.  Someone here told me to change CV29 to turn off DC mode.  I have no idea why, but I forgot to change it (now there's a brilliant statement).  Valuable lesson learned.

Just yesterday my wife was telling me that there's 3 reasons you start to forget things when you're past 50 - stress, being tired and......uh.....oh, nevermind. 

   

Jim "He'll regret it to his dyin day, if ever he lives that long." - Squire Danaher, The Quiet Man
  • Member since
    February 2008
  • 416 posts
Posted by UpNorth on Thursday, March 13, 2008 10:04 PM
That statement should end with.. "Uh  Oh !..  I forget the third one" ...

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!

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!