Hi all,
I have been out of MRR for several years and just came back and start to pick things up.
I recently installed a Digitrx DZ123PS decoder to an Atlas Silverline DASH 8-40CW. The loco runs great. But when I used JMRI to do speed match I found some issue. The decoder seems not to follow the speed table setup. I set the speed table to have the same value for throttle 10%-50% (step 5- step 14 in speed table) but the loco still can change the speed when I turn the throttle. To make it worse, the loco is extremely sensitive to the throttle input. At 40% throttle, the speed is 45MPH; at 39%, the speed drops to 40MPH; at 38%, the speed is 35MPH. In a few turn of throttle, at about 32%, the speed drops to 17MPH; then the speed would not change when I dial the throttle until down to 10%.
I am wondering if this is an indication of a malfuction decoder. Or I may set the decoder wrongly. The decoder is set to 28/128 mode. I use JMRI and Digitrax DCS 52 for decoder programming.
Jerry
There are two potential issues here.
First, that decoder does not have BEMF, so it won't be able to maintain a perfect speed setting through any binding in the mechanism, changes in grade, or even the increased drag of running through curves.
Second, are you using a JMRI throttle or the Zephyr console? The potentiometer on the Zephyr is not going to give fine enough cvontrol to see just what speed step you are one. A JMRI throttle can, or one of the DT series throttles, or the new UT6.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hi Randy,
Many thanks for the suggestions. Yes, I was using a Zephyr cosole for programming. Do you think I can check the CV data to confirm if Zephyr was able to write the correct CV setting?
I don't mean for the programming. But yes, you can read the CVs fine with the Zephyr and verify they are what you think you set them to. Since you have it hooked to JMRI through the built in USB port, you can use JMRI to do this as well.
I was speakign of then test runnign it to see how well it followed those settings - witht he Zephyr's built in throttle it's hard to change speed step by step, the control is a bit too coarse. But since you are using JMRI, you can open a computer throttle and advance speed one step at a time.
Oh, I see, Randy. Yes, I was using UT6 to control, which indeed gives me very precise reading and control. Thanks again.