Just purchased an Athearn Genesis fef-2 steam with tsunami. With 9 athearn passenger cars (not very heavy) at certain times the engine will reduce speed and then resume set speed without touching the throttle (digitraxx). I read in the tsunami guide about load compensation but my eyes starting glazing over and I just couldnt figure what CV's to adjust. At this point I did not adjust any cv's. What I was able to make of the manuel was that there are a few cv's that might need an adjustment? What would they be? and what woud be their value? Or if something else is involved, please let me know.
Thanks
Joe C.
I know what you mean about reading those manuals until your eyes glaze over.
Don't have an answer, but do see a couple of questions that might help others.
Does it always slow down at the same spot, hill, pulling a sharp curve, going through turnouts?
If you have no hills or sharp curves, are your feeders evenly spaced around the layout?
Just a couple of things that come to mind.
Good luck,
Richard
I do have grades. And it happens either going up or coming down the grade.
If it's only on the grades, it may be a matter of gear or drivetrain slop, not the decoder.
That said, doing a reset on the decoder should clear any strange CV settings as the cause.
In the manual, the sections on BEMF are the ones to examine in regards to adjusting the CVs that are the most likely cause if the decoder is a problem.
Mike Lehman
Urbana, IL
dominic c With 9 athearn passenger cars (not very heavy) at certain times the engine will reduce speed and then resume set speed without touching the throttle (digitraxx).
With 9 athearn passenger cars (not very heavy) at certain times the engine will reduce speed and then resume set speed without touching the throttle (digitraxx).
First we need to establish what's causing the speed reduction.
1) Is it moving at an uneven speed at slow speeds or high speeds?
If at slows down or stops at slow speeds, then BEMF can help.If it slows down at high speeds when entering turns, then that is expected behavior and BEMF will fix that. If it slows down and speeds up on straight sections, then track voltage variations could be the issue and BEMF will NOT fix that.
BEMF has no "magic" universal CV settings for optimal performance. You have to follow the guide in the book for setting it up as each engine varies. (Sorry to report) It's sort of like tuning an old car engine with a new cam. Sometimes you just have to tweek it till it runs right.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
It seems to slow down on a grade. Ands when I ran it byitself the slow down stopped
Joe C
Sounds like gravity is still working on planet earth. When things go up hill, cars, locomotives, and model trains will slow down, and this is normal. When going down a grade, they will speed up.
The more weight on the train, the more it will slow down. No weight, no slow down.
Engineers have to make throttle adjustments to compensate for this when running real trains. Modeles are no different. However, since DCC has come along, there is an electronic compensator circuit called BEMF that can automatically take care of this for us. You have to know how to set it up.
But, I can't tell you how because even though my decoders have it, I choose not to use it because it makes me control the train more realistically. There are a couple of CV's that have to be changed.
But one other thing. Locomotive manufacturers put in cheaper decoders in their locomotives than what you would normaly buy and instal yourself. So they may not have BEMF or the CV's to adjust it with. You should be able to find out what settings are available for the decoder you have on the locomotive manufacturers web site.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Usually, that decoder is set up with BEMF as default. Maybe a reset is in order. Changing the BEMF CV's can be quite a challenge. I just did it on a QSI decoder, and it pretty much worked ok. In reality, I think I got lucky.....
Mike C.
I have a Bachmann 2-10-0 that was an "OK" runner. I decided to follow the instruction and tune the motor feedback. If I recall correctly Soundtraxx calls it the PI loop or the PID loop. It seems complicated but is actually fairly easy if you take it one simple step at a time. I did not get too crazy and go for each setting to be optimal just very good. Anyway, when i was done it went from being an OK runner to a very good runner.
By the way, I never tried consisting it, but I understand that once feedback is set up it makes it difficult for consisting as the engine will try to run at a very precisie speed vs another engine in the consist that may be running at a slightly different speed.
Mark