The trim CVs are for the speed tables, completely different from the throttle speed steps.
There are only 28 steps in the speed tables, plus forward and reverse trim.Most decoders do interpolation to spread the 28 values across 128 speed steps when using 128 speed step mode. Many systems still default to 28 step speed steps, with 14 and 128 as options. Digitrax defaults to 128 with 14 and 28 as options.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
CSX Robert SouthPenn My NCE Power Pro throttle has speed steps from 0 to 126. This is extreamly close to the 128 speed steps most locomotives run on... The reason your thtrottle goes from 0 to 126 is because the "128 speed steps" include 'stop'(0) and 'emergency stop',so there really are only 126 steps.
SouthPenn My NCE Power Pro throttle has speed steps from 0 to 126. This is extreamly close to the 128 speed steps most locomotives run on...
The reason your thtrottle goes from 0 to 126 is because the "128 speed steps" include 'stop'(0) and 'emergency stop',so there really are only 126 steps.
I thought it was because the first speed CV was for Foward Trim, and the last was for Reverse Trim.
I guess it could very by manufacturer.
SouthPennMy NCE Power Pro throttle has speed steps from 0 to 126. This is extreamly close to the 128 speed steps most locomotives run on...
My NCE Power Pro throttle has speed steps from 0 to 126. This is extreamly close to the 128 speed steps most locomotives run on. BUT, a setting on '60' on the throttle gives widely different speeds depending on the locomotive. There is even a noticeable differences between my Stewart/Kato locomotives. Blue Box Athearns run very fast at '60' compared to my BLI.
Some of the differences I attribute to the different brand and age of the decoder that is installed in the locomotives. Older decoders don't have all the fancy motor tunning as the newer ones.
Be careful, you can drive yourself nuts trying to speed match locomotives. You could even fall into the 'rivet counters' black hole.
Thanks Randy.
You need a throttle with an encoder to know absoute speed steps. A DT402, or else an interface with JMRI on your computer, JMRI has on-screen throttles and/or you can use smartphones as wireless throttles, and those have specific speed steps.
When I got back into the hobby several years ago I bought a Digitrax Zephyr so I could start off in DCC. Well after years of research, building models to get my skills back up I have finally reached the point where I have some track down and I'm running some trains.
I read a lot on the forums and in the MRR press about how a locomotive performs at a certain speed step. My question is; How do you tell what speed step you are on? My Zephyr and UT4 both use a rheostat to adjust the throttle just like the old DC power packs. Are the speed steps that everyone refers to simply a subjective judgement based on the position of the knob that controls the throttle or are they a definite setting that I am missing somewhere?
Jeff