Hey Guys,
Hope someone can help me. New here, and to the hobby. Bought my son an HO set. And got addicted myself. Ive watched tons of videos, many internet searches. This forum pops up a lot. I am attempting to speedmatch a Walthers es44 Gevo, and a walthers sd70ace, both with esu oem. Although the gevo is a 2017, the sd70 is this years latest run. I am using an NCE powercab. When i do a cv2, cv5, and cv6. The wierdest thing happens. At step 1, perfect match. At step 28, perfect match, at step 14, perfect match. At step 3,4,5...15,17,18, anything in between. Gevo slowly runs away from SD70. What did i screw up?
to the forum. I'll give your post a bump because I don't have an answer.
Does it cause problems when the locos are actually consisited together?
Henry
COB Potomac & Northern
Shenandoah Valley
The short answer is that you didn't screw up. There are two methods of speed matching and you have found the limitations of the first method.
CV2, CV5 and CV6 are used for basic speed matching. Most modern decoders (which is sounds like these are) have 28 programmable Speed steps. CV2 sets the minimum speed (speed step 1), CV 5 does step 14, CV 6 does speed step 28. Everything in between those three speed steps in a linear interpolation. Motors are not necessarily linear which you have imperically discovered.
This is where the second more involved methord of speed curving using all 28 speed steps helps speed matching locomotives. (even though these decoders are 128 step, steps between the 28 steps are interpolated). Each speed step can be independently tuned to match the locomotives.
CV's 67-94 are the speed curve CV's for a ESU decoder (may want to double check manual on this).
There are many ways of getting this all to match. running them around on an oval track at each step until they match is one way. I prefer to use a set of rollers and match all my locomotives to a common speed table. This way all my locomotives run with each other since each speed step correlates to a specifict speed not necessarily just another particular locomotive.
Colorado Front Range Railroad: http://www.coloradofrontrangerr.com/
Renegade1c prefer to use a set of rollers and match all my locomotives to a common speed table. This way all my locomotives run with each other since each speed step correlates to a specifict speed not necessarily just another particular locomotive.
How are you measuring speed, if they are on rollers?
Yea, I would think that you would need to visually see how they run together, as I would think individual decoders, and brands of locomotives would act a little different, even though they are matched to the same speed table.
BUT, I've never done any speed matching, except like the old days, find 2 locos that run good together, and use the same address. The low tech. way.
Mike.
My You Tube
Welcome. First thing, what are your settings in CV 2, 6 & 5 you do remember that CV 5 set max. speed and CV 6 mid range speed and that CV 5 must be set higher than CV 6 or some strange things may happen. Also set CV 2 first and then CV 5 for top speed, match as best as you can and then set CV 6 somewhere mid range and adjust as needed. Usually works for me.
When you say the one runs away - do you mean slowly gets further away, or it's like the one takes off realtive to the other?
If the former - it's probably fine. There is no need for the locos to run in perfect lockstep for them to MU effectively.
One thing you might try (and you'll probably have to redo the 3 steps again) is to run the ESU automatic BEMF calibration. This explains how:
http://www.sbs4dcc.com/tutorialstipstricks/esuloksoundmotorautotune.html
Make sure you have enough track space clear in front of each loco (do one at a time). It will take off like a shot for a short distance - 4 to 6 feet.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks for all the replies, yours most helpfull Randy, it does slowly pull away from the sd70. Being new, i just didnt know this was ok. And was afraid f tearing something up. Or prematurely wearing the locos.
Hey, thanks for your help. I guess from all the videos i have watched i had assumed that the speed curve would somehow be altered by adjusting the 3 CV's. The Esu manual that comes with these only lists a few cv's. They must have changed the OEM decoder up. I was a little dissapointed in the Gevos prime mover sound. High pitched rattling and low volume The 2018 SD 70 prime mover sounds like the LOKsound prime mover. Lots of low rumble and the turbo sounds authentic. And its volume so much greater the gevo's mover cant be heard over it.
BigDaddy Renegade1c prefer to use a set of rollers and match all my locomotives to a common speed table. This way all my locomotives run with each other since each speed step correlates to a specifict speed not necessarily just another particular locomotive. How are you measuring speed, if they are on rollers?
I use a roller speedometer. Here is the one I have found here. It is under one of the wheels Speeds are shown in JMRI. The plus sides is that if I use Programming on the Main,changes made to the speed table are made in real time. This makes doing the speed tables only take about 15-20 minutes per locomotive.
Here is my speed chart. I only program the steps in green. The rest are interpolated by JMRI. The check boxes below slide bars indicate whether you want that speed step to be indepentently control or have it linked and interpolated by the software between specified steps. Since the majority of how my locomotives are run are in the first 10 steps. i program them to match and only do every forth step after that and let JMRI interpolate the steps in between. Ocasionally I tweak the intermediate steps but not very often.
Renegade, thanks for the explanation.
turns out, things get even weirder. i fixed it. but it took more internet searches. finally came across an article on the NCE information station. ncedcc.zendesk.com. That explained that all manufacturers do not keep with NMRA standards. Particularly ESU. They use to use a system origionally developed by Marklin MFX, in which, CV's 2,5, and 6are active in both modes. with the values of CV's 67 to 94 scaled in between. The actual article was about Loksound. But, ill be damned, when i applied the principles to my ESU, OEM decoders. It worked out just the same. Sort of. When i adjusted CV's 68-79, and 81-93. Everything started falling into place. However, 94 must remain 255. And that has to be addressed through CV5. And some CV's were stubborn (maybe) probably something else i dont know. And reverted to their old settings, causing huge speedjumps, in places. But you were right, spent a couple of hours running the loco's around a track. Worked out good though. Thanks!