Digitrax throttle control

Discussion in 'DCC & Electronics' started by eric halpin, Jul 4, 2007.

  1. eric halpin

    eric halpin Eric Halpin


    Some months ago when I first started using my Dt300, I thought that every click on the throttle adjusted the speed by about 1-2%. Now I notice that each click varies by 3-6% and sometimes more. Can you explain to me why this is or what has happened? Is it something to do with the programmed speed setting?

  2. trainnut65

    trainnut65 Member

    Maybe the loco is running better. I don't think i would have noticed 1-2% speed increase but i guess if you run the same loco everyday then you mite can tell it speeds up more on the same setting. and i don't know of a setting on the controller that gives it more power per click on the throttle. There is a top speed setting and you can control how fast it gets to top speed with the CV values. But i dont know of a setting that controls the voltage to the decoder per click on the throttle. This could be a real wall1
  3. MasonJar

    MasonJar It's not rocket surgery

    How many speed steps is the decoder using? If each "click" corresponds to one step, you will see a difference between a decoder that uses 14 or 28 steps versus those that use 128 steps.

    Has this happened with the same loco/decoder with the same settings preserved? Something has to have changed to make it so, but the key is to find out what. For example, we had to change the Digitrax Zephyr at the Merrickville club the other day to tell it that it was addressing a Lenz decoder with 28 speed steps, instead of other decoders with 128 steps.

  4. railwaybob

    railwaybob Member

    The faster you "twirl" the throttle knob, the faster the "percentage" numbers will increase. That is, there isn't a one-to-one ratio between the speed with which the throttle numbers and the speed with which you turn the knob. Digitrax calls this "ballistic tracking".

    On page 2 of the DT300 manual, it states that "As you turn the DT300 throttle knobs you will feel a mechanical detente (and hear a beep if your throttle is set up for beeps and clicks). Each time you move the knob, the system processes information. In some cases, the LCD display will not change each time you feel the detente. In the case of increasing and decreasing loco speed, this is because each detente does not equal an increase or decrease of 1% speed. If your DT300 is set up for ballistic tracking, the speed you rotate the encoder (throttle knob) will affect how the display changes. You can customize the tracking characteristics of these knobs for either straight line (normal) tracking or ballistic tracking. With straight line tracking each movement of the knob causes a fixed rate of change. With ballistic tracking, the faster you increase or decrease the the throttle knob, the faster the data changes in the throttle. Your DT300 was shipped with ballistic tracking as the factory default setting."

    An example of this lack of a one-to-one ration, assume you want to dial up a locomotive in the high number range - eg 9899. Simply twirl the left knob real fast and the 98 appears really fast (you don't have to go through 1, 2, 3, 4, . . . . . . 95, 96, 97, 98). Then twirl the right knob real fast and the 99 appears.

    For a technical description of how the knobs function, read Pages 2 of your Digitrax user's manual
  5. eric halpin

    eric halpin Eric Halpin

    Dt 300 throttle


    I think I get it. I shall recheck to see what speed step is programed as well as the balastic setting, etc. Both of these checks will be somewhat difficult for me as a novice but shall check. When I stated about turning the throttle, in both cases it was a slow steady increase. Will keep you posted.

  6. avlisk

    avlisk New Member

    I don't know if this will help, but here is something that occurred with my Digitrax DZ143 decoder. Suddenly out of nowhere, one of my locos began running in the opposite direction. Concurrently, when I turned on the headlights, function #2 would activate. As I only run headlight functions, and clipped the leads to the purple and green wires, I had a mystery. Upon reading the BLI website, it said "if using NCE Procab, when changing a long address, one must first reprogram the long address to 0000, and then enter the new long address". (I paraphrase). I figured I didn't have a BLI, but it couldn't hurt, so I did that with the DZ143, and it worked! It is now running correctly again. Perhaps you could reprogram to long address 0000, and start anew. By the way, resetting CV8 to 008 didn't help.
  7. Gary Pfeil

    Gary Pfeil Active Member

    The readout on the throtle goes from 1 to 100. Using 28 speed steps, each increment will be either 3 or 4 steps. Using 128 speed steps, the increments will mostly be one, but sometimes there will be no change. I believe the applied voltage will still increase, but the display remains the same.
  8. eric halpin

    eric halpin Eric Halpin

    digitrax throttle question

    Both good bits of info. I suspect I have reprogrammed the throttle to 28 speed steps instead of the original 128??!! Thanks for the help and info.


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