finally went and programmed a consist which consisted of two atlas ho diesels,a classic gp7 with an nce decoder and a atlas gp 38 with the original factory decoder.the two diesel’s after they were consisted didn’t run together well as one is faster than the other.here’s where i run into problems.are the cv’s start voltage and etc adjusted before you program the consist or after the two loco’s are programmed for consist?.im so tired of reading the manual.i suppose it’s right in front of me but i must be overlooking it.thanks for any and all help.terry…
I have never programmed a consist, but I would expect that each loco should have its V-Start pre-determined and set since each loco needs its unique minimum voltage to get underway. Once that is done, you must also, I believe, ensure that both locos respond to the same number of speed steps so that an increase in the throttle is matched step for step.
As always, I will be sure to learn something from others who actually have done this. [:)]
Run the trains individually and set the start voltage for each individually. Make sure each has the same number of speed steps.
Take a look at your manuals for your decoders. There’s typically a mid speed CV, top speed CV, speed step curve parameter, or speed table for decoders these days. Adjusting these for the slow loco may help a great deal. First try adjusting mid speed CV and top speed CV (if available in parameter list) Then try the speed step curve parameter. Lastly (the most time consuming) is adjusting the individual steps in the speed step table. The later can get quite complex and is best explained by your decoders manual.
I or someone else might be able to step you through it. I had to do it with my E units from Athearn. I consisted 3 of them. The first took 20 minutes to match up. The second only 5 minutes.
If you have back-emf/hyperdrive, you’ll need to tone down the correction factor or turn off these features all together, or they will fight with one another constantly adjusting their speed.
thank’s for both of your replie’s,much appreciated.im sure after i do a few of the cv adjustment’s i will learn the proper procedure.i will do as dig grif suggested.my problem is learning how to do the proper sequence’s of changing the cv’s.i get totally lost. i guess i’m suppose to change the cv’s for each loco while on the programming track and then go and add them to the consist?thank’s for hearing me out.terry…
In addition to adjusting the Start, Mid, and Max voltage CVs already mentioned, make sure both decoders are set on the same number of speed steps. Most NCE decoders default to 28 speed steps, but I have no idea how Atlas decoders are set.
You can Program on the main “POM” for most of these parameters.
Terry,
I’ll try and help also by explaning how I do it, which does involve some trial and error. You mentioned one has a NCE decoder and the other is factory installed. Since I don’t know which decoder is in the factory unit let’s look at the NCE. Make your consist and set the direction for each loco, which sounds like you have done. Next uncouple them and slowly give them power, if they start together good, if not adjust the start voltage, I don’t remember which cv number it is, on the slower one until both of them take off at about the same time. Remember, this is not an exact science and if mine will run over five feet and not couple, I have found that to be “good enough”.
Sometimes I find that when they both start together they run together, sometimes not. When they don’t I adjust the faster of the two by changing mid range & max until they get close. You can do this by using on the main progaming, you don’t have to put them on the programing track. I believe cv 5 & 6 adjust the two cv’s for mid range & max so I keep fooling with them until they run at about the same speed. The reason I mentioned let’s look at the NCE is because I know those decoders, at least the ones I’ve gotten from them, support mid range & max programming while some others do not.
I haven’t had my NCE system for long but I did run Rail Command for a number of years and Onboard before that and while I waited a number of years to make the switch to DCC I’m glad I did. I believe after you have practiced this a few times you’ll be an old hand at it. Check the cv numbers for mid range and max before trying this as I quoted this from memory and could be wrong.
Good luck.
Clay Smith
I don’t believe the Atlas factory installed decoder supports the V-mid and V-max CV’s. Check the Atlas decoder manual, either in the box the loco came in, or online. I"m in the process of replacing the Atlas decoders with NCE decoders in my Atlas GP38’s and Dash 8-40B and BW’s . Otherwise, you have to set up speed tables to match them closely. That can be done easily if you have a computer set up with your railroad, using JMRI or a commercial program.
thank’s to all for your help.i’ve printed this all out and will go over to the layout wednesday morning and see if i can do it.terry…