Hey Guys,
I have two engines that I am trying to speedmatch. The first is a Proto 2K SD60E and the second is a Intermountain Gevo. I have installed Tsunami Sound decoders in each. I have programmed CV29 to option 18 which allows me to use the loadable speed table which consists of 28 speed steps.
On the Zephyr it doesn't have exact speed steps like say the MRC prodigy does so I am using certain points on the throttle to compare these two engines. Now I have an app that will calculate scale speeds so first I wrote down all the speeds for the proto engine at 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 and full and then did the same with the Gevo with the Gevo being about 25% faster.
When trying to slow down the Gevo to match I am not sure which CVs to change as the CVs to change the speed steps go from CV67 all the way to CV94.
I have tried to speedmatch these two engines starting with CV67 and going up and I have tried starting with CV94 and working down and although change has been made, the changes seem erratic at best.
What is the best way to speedmatch using this system. Just for reference my P2K engine at full runs 54 scale MPH and the Gevo I have down to 64 MPH.
Any help would be greatly appreciated.
Will
The best thing you could do is to download the decoderpro program from JMRI.
If you are trying to do this all manually, you have a lot of work cut out for you. What I would do is to set CV 67 for both engines to get the starting speed the same. Then you can set CV 94 to get the max speeds the same. Since you won't be able to set CV 94 to get the slower loco to run faster, you will have to set it to get the faster loco to run slower. Now if you assume that both engines have a linear speed curve between min and max speed (which is not always the case), you can adjust all the other CVs between 67 and 94 (26 of them?) to give you 1/26th of the speed difference between min and max. For example, whichever CV corresponds to speed step 14 would be adjusted to give you 50% speed.
The joy of speed matching Tsunamis. That's about the easiest way you can do it, set the first and last entries to match teh starting speed and the top speed, then work along the middle fo the table. It should really be close enough if you get the start, top, and moddle matched close, this doesn't have to be dead on.
Most of the time that's all you have to match, but since Tsunamis don't support the simple way of doing this using CV2, 6, and 5, you have to go to the full speed tables.
--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 the responses guys these suggestions got me on the right track. I did manage to figure it all out. I first went and changed CV29 to 18 which allows me to program in the 28 step speed table, then I entered in the values for all 28 speedsteps CV67 to CV94 according to my tsunami manual.
Next I adjusted the starting voltage CV2, Mid CV6 and then CV5 Max voltage to the recommendation of my digitrax manual. The next step in the process was setting CV25 to 2 which gave me a linear speed curve.
The final step in the process was adjusting both the forward trim CV66 and the reverse trim CV95. I compared the two engines at several speed points on the dial and found the gevo was about 38% faster so I took both the forward and reverse trims and changed them from 128 to 79 (38%) and wouldn't you know it was spot on and I do mean spot on.
Again gents thank you for getting pointed in the right direction.
Tsunamis don;t recognize CV5 and CV6, so you have to do it all with the speed tables. They DO use CV2 so you can adjust the start voltage, but this will conflict with CV67, the first speed step in the table.
willjayna Thanks for the responses guys these suggestions got me on the right track. I did manage to figure it all out. I first went and changed CV29 to 18 which allows me to program in the 28 step speed table, then I entered in the values for all 28 speedsteps CV67 to CV94 according to my tsunami manual. Next I adjusted the starting voltage CV2, Mid CV6 and then CV5 Max voltage to the recommendation of my digitrax manual. The next step in the process was setting CV25 to 2 which gave me a linear speed curve.
Not sure what you did, but I guess you somehow got lucky. The Tsunami does not support CVs 5 and 6. It is possible that the loco reacted by jumping in one direction or the other as if it was accepting the CV changes. But it does that whether or not a particular CV is supported so it was just fooling you. So far as a value of 2 in CV 25 goes, yes it gives you a linear speed curve but it is a linear curve as defined in the decoder programming. It is not a curve using the user defined values that you put in CVs 67 to 94. You would have to have a value of 16 in CV 25 to use the user defined values. See page 22 of the Tsunami diesel technical reference, http://www.soundtraxx.com/manuals/tsunami_diesel_technical_reference_0213.pdf