Low speed problem

[FurkaSOCal]

I recently converted one of my locomotives to DCC and I noticed that it sort of "jerks around" on speed step 1. As soon as I switch to speed step 2, everything is fine and it drives very smoothly. I am using a ESU loksound v4 decoder and have access to the lokprogrammer device. Do you think this is a mechanical issue or a programming issue? I don't recall any rough operation when it was analogue, and speed step 2 is still very slow but there are no problems...

I made a short video of the problem for those interested:

 

[Greg Elmassian]

looks like BEMF setting... could also be PWM frequency and if ESU has a "kickstart" setting...

 

[Neil Robinson]

Have you tried automatic calibration? if not it's worth trying but a little scary first time.
It's one of the features that I really like about ESU decoders.
Find your Loksound manual, if you don't have one download one from this site. ESU - Electronic Solutions Ulm GmbH & Co. KG: Digital decoders
Look up the section on "Automatic calibration of motor" in the Motor control section. It's on page 66 of the latest V5 manual. This procedure doesn't differ from the V4 version.
Just in case it goes pear shaped I suggest you read and note the values of CVs 51, 52, 53, 54 and 55 before you start. You can then revert to the original values if you wish.

 

[FurkaSOCal]

No I haven't tinkered with too many of the CVs, I just downloaded the project from ESU's website for this locomotive and changed some of the function mapping. I'll see if I can figure that out and give it a try!

 

[FurkaSOCal]

update: I tried out the automatic calibration feature and it worked! Locomotive runs very smooth now. Thanks for the tips!

 

[Greg Elmassian]

That behavior you observed is classic BEMF issues, by the way, so you will spot it right away next time. Good for you.

Greg

 

[Gavin Sowry]

I'm not a proponent of DCC etc. etc., in fact far from it. Why I'm commenting, is that I was struck by civility of this thread. Man has a problem, askes a question, and gets quality reply.
No beating about the bush, no one pushing their own barrow. Congratulations, chaps.