Model Railroading > DCC lighting

Is there a decoder with which it is possible to do the following?

F0 turns on the headlight
Fx dims the headlight (for trailing DPUs, meets and in yards)
F1 turns on the ditchlites
F2 makes them flash alternately
F3 turns on the rear light

I mostly use Digitrax and NCE decoders and can't figure it out on either one of those. They tie the headlight and ditchlites together so they can't be controlled separately and Digitrax insists the headlights be directional.

I would say that all of that is possible. You just need to wire the different lights to the different "F" (output) points on the decoder, corresponding to the output you want to use, and set your CV's accordingly. I use NCE and if you check their manual that comes with the decoder, it should tell you which CV's to use, and you can also change the output of the CV's with function mapping.

If you don't have a manual, then you can download them at http://www.ncedcc.com

I'm not that familiar with the Digitrax decoders, but I'm sure they would work in the same way.

Ron Evans
Golden Valley, AZ

The example NCE has in their directions have all the front lights come on with F0 and flash with F2. I can't find a way to separate the flashing ditchlites and the headlight. I have the headlight, rear light, right ditchlite and left ditchlite all wired to different outputs.

I think it should be possible but I'd like to hear from someone who's actually accomplished it.



Edited 1 time(s). Last edit at 08/25/10 20:01 by pmack.

Try a Train Control Systems decoder. Of course you'll need one with at least 4 function outputs, but there's no problem doing what you want. See http://www.tcsdcc.com/Customer_Content/Technical_Info/Tech_Manuals/Additional.pdf
Scroll down to the part about ditch lights.

Barry Draper

You are correct except you might be able to trick the decoder.

If your headlight is not told to illuminate with F0, then you can use F0 to turn the ditchlights on and then have F2 make them alternately flash. You just have to change the headlight to illuminate with a different function, say F1. Then the rear light with F3. The downside to this is that you can't dim the headlight as the dimmer function is related to F0 or directionality.

To do the above, assuming that the headlight is wired to output 1, program CV35 to 1. Assuming the rear light is wired to output 2, program CV37 to 2. Assuming the ditchlights are wired to outputs 3 and 4, program CV33 and CV34 to 12. Program CV36 to 12 as well. Then program CV122 to 56 (184 for LEDs) and CV123 to 60 (188 for LEDs).

Now, F0 should only turn on the ditchlights, F1 the headlight, and F3 the rear light. F2 will then make the ditchlights flash.

I don't think you will be able to dim the headlight but you could try setting CV120 to 44 (172 for LEDs) and then when you want to dim the headlight you could just set the throttle for reverse. This setting is for "bright in forward dim in reverse". This likely will not work since all of the lights have been changed to be independent of direction.

NCE decoders are pretty limited on being able to set any function to any output and have any lighting effect. I've just compromised and gone with it since I like the NCE decoders so much. Lenz decoders do allow you to easily accomplish what you're after and I think Digitrax ones might as well. I'm not positive but I think TCS decoders do as well. The downside to the Lenz decoders is the flash of the ditchlights is programmed to turn each light completely off as they alternately flash. Other decoders dim the ditchlights as they flash which is more realistic of the prototype.

Rio Grande Fan
Denver, CO







pmack Wrote:
-------------------------------------------------------
> The example NCE has in their directions have all
> the front lights come on with F0 and flash with
> F2. I can't find a way to separate the flashing
> ditchlites and the headlight. I have the
> headlight, rear light, right ditchlite and left
> ditchlite all wired to different outputs.
>
> I think it should be possible but I'd like to hear
> from someone who's actually accomplished it.

What function output is each bulb connected to?

Thanks RioGrandeFan, I got it to work! Somewhere I had a misstep and pressing F2 caused the right ditchlite to blink like a turn signal and the left to turn off when the sequence finished. I tried again and got it right. The headlight is even dimmable with F4! The compromise of having F0 and F1 reversed is acceptable. FWIW, CV34 and 36 can be 0 so to this is what I ended up with:
CV33=12
CV34=0
CV35=1
CV36=0
CV37=2
CV120=160 (for LEDs, else 32)
CV121=164 (for LEDs, else 36)
CV122=184 (for LEDs, else 56)
CV123=188 (for LEDs, else 60)

Operation is as follows, F1 on and F4 on turns the headlight on dim. Turning off F4 switches the headlight to bright. FO turns on the ditchlights and F2 causes them to flash alternately. F3 and F8 turn on the rear light dim and turning off F8 switches the rear light to bright.

I had the front headlight connected to output 1, rear light to output 2, right ditchlite to output 3 and left to output 4.



Edited 1 time(s). Last edit at 08/27/10 22:00 by pmack.