Since I switched to DCC, I bought one DCC equipped loco and had decoder sinstalled in three of my former DC locos. I just received a USB interface for my Power Cab system and I will download JMRI as soon as possible. I would like to have a easy to read (and easy to understand) text to learn how to program good speed curves in those locos.
Can anyone help me find a good reference?
Guy
Modeling CNR in the 50's
Guy,
Start 'simple' - You can really mess up with speed tables! First, you need to know if the decoder supports speed tables(read the decoder info). Also, does the decoder support Vstart/Vmid/Vhigh(also in the paper or on-line decoder documentation)?
You will want to create a 'Roster Entry' for your engine, and program the DCC address into the decoder on the Program Track if it is still a '03'. I do this for all of my engines, even if they have been 'programmed' earlier.
Now you can place the engine on the 'main' and verify that it responds to it's DCC address. If all checks out, you can use Decoder Pro to 'Program on the Main' and adjust the speed table values.
On the JMRI Decoder Pro screen, there is a tab for 'Basic Speed Control' . The default is normally set to use Vstart/Vmid/Vhigh - this will produce a speed table based upon the values you input. I set Vstart so that position 1 on my throttle just starts the engine moving. I set Vhigh to about 70 scale mph for most of my freight diesels, and set Vmid for about 40 scale mph. Decoder Pro will build a speed table based on that information. I 'speed match' all of my second generation engines to run on the above parameters. I use a 'measured' distance on the club layout to do this.
If you want to create your own customized speed table, go to the 'Speed Table' tab and adjust the 'slider' bars to create your own. This will disable the automatic speed table calculation done with the 'Basic Speed Control' tab.
A couple of pointers:
I would also read all of the JMRI documentation on their web site, and join the Yahoo JMRI Group - Lots of info there. Most of the 'gotcha' stuff is documented. No need to to re-invent the wheel!
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Thank you Jim. I will follow you advice.
jrbernier Warm up your engine with about 15-20 minutes of running before playing with Decoder Pro. You need to let the oil/gear lube warm up and get the bearings saturated. If you do not do this, speeds can change after you have done all of this work!
Warm up your engine with about 15-20 minutes of running before playing with Decoder Pro. You need to let the oil/gear lube warm up and get the bearings saturated. If you do not do this, speeds can change after you have done all of this work!
For another opinion on this............
I have done over 50 engines for a friend, using the speed tables for all of them. I tried the let them warm up first method. I have a speedometer, so I let them run around until the speed no longer increases before I try setting the speed curves. Some engines will increase 10 to 15 (or more) mph between cold and hot, others will reach their max speed after only a few laps around the loop.
I set the max speed first (he wanted 60 smph) and then set the intermediate speeds (15, 30, and 45). I invariably find that the locos with the large initial speed changes will become the problem children, as the motor cools off while I'm setting the intermediate speeds. Going back to check the max speed always finds it off.
The other thing I find of concern is that the normal operation on the model railroad is starting and stopping, not continuous running (at least for an operating railroad, not display or for my own amusement running). So the motor does not have time or distance to reach its maximum temperature (speed) very often.
I don't have the answer to all this, and have resigned myself to do the best I can. But being an engineer I sort of get bothered by things like this that don't seem to have a ready solution.
Keep in mind you may not need speed curves. Try setting CV 5 and 6 for the top and midrange speeds using in effect a "straight line" speed curve and see how that works. Unless you want some special effect, like an engine that runs at 1/4 speed at 1/2 power and full speed at full power, a straight line normally is all you need.
wjstix Keep in mind you may not need speed curves. Try setting CV 5 and 6 for the top and midrange speeds using in effect a "straight line" speed curve and see how that works. Unless you want some special effect, like an engine that runs at 1/4 speed at 1/2 power and full speed at full power, a straight line normally is all you need.
Assuming his decoder has CVs 5 and 6.
OP, what decoder do you have?
Every current decoder EXCEPT Tsunami supports 2, 5, and 6. Tsunami does 2 and 5. Come on, Soundtraxx.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker Every current decoder EXCEPT Tsunami supports 2, 5, and 6. Tsunami does 2 and 5. Come on, Soundtraxx. --Randy
Randy: Unless they have changed something, the Tsunami only has CV 2. I'm looking at page 61 of the Tsunami diesel Users Guide: http://www.soundtraxx.com/manuals/Users%20Guide%20Diesel.pdf.
I'm also pretty certain that I've seen other decoders that have only Vmax and Vmin, with no Vmid, but which one that was escapes me at the moment. You did say "current" decoders, but we have no way of knowing what vintage decoder someone might have if they happen to stumble on this thread in the future.
IIRC, some of the really old Digitrax decoders(DH120???) do not support CV6 or custom speed tables. I friend has quite a roster of engines with Digitrax DH120/DH121 decoders. He has been replacing them with Digitrax DH123 and NCE D13SRJ decoders when they are on sale.
Most 'new' decoders support Vstart/Vmid/Vhigh and custom speed tables(except Tsunami's as noted).