Independent Head/rear light control

[steamfreightboy]

What CVs do you have to program in order to gain independent control of the front and rear lights on a loco? I remember seeing how to do it before in a DCC corner, and have done it for one of my engines, but I forget what issue it was in. Also, how do you map the rear lights so it is controlled by F1 versus F4?

Thanks,

sfb

[steamfreightboy]

One I think is an MRC sound decoder and the other is NCE. However, i have not been able to program the MRC CVs on my powercab for some reason.

[tstage]

sfb,

If you know the make and model of your decoders, you can often download the decoder manuals right off the manufacturer's website.  Most of the time all your answers and information is found there.

Tom

[cacole]

Different manufacturers use different CVs to control lighting functions. 

For example,

TCS uses CVs 49 for the headlight, 50 for the backup light, and 51 or 52 for a mars, strobe, ditch lights, etc., IF the particular decoder you have supports more than just 49 and 50.
NCE uses CVs 118, 120, 121, and 122.
MRC doesn't say what CVs to use in their documentation for a Sounder.
QSI doesn't list the lighting function CVs in their Revolution booklet, so you have to download a Technical Reference Manual from their web site.
SoundTraxx also has a detailed Technical Reference Manual that you have to consult.

So you have to have the documentation for your specific decoder type to know which CVs to change.

[jalajoie]

About your NCE decoder here is what I do:

First Map F1 to control the rear light

To do it Set CV34=0 default is 2 and Set CV35=2 default is 4

If you want to Dim the front light with F4: Set CV120=32. This is for incandescent lamps. For LED set CV120=160. This will give you complete control independently of the direction of travel. Default for CV120 is 1

If you want to Dim the rear light with F8: Set CV121 to 36. This is for incandescent lamps. For LED set CV121=164. This will give you complete control independently of the direction of travel. Default for CV121 is 2.

This give me independent light and independent dimming of both front and rear light regardless of the direction of travel.

These are my preferences the use of JMRI is invaluable when playing with sophisticated light functions or sound decoders. 

[maxman]

jalajoie

About your NCE decoder here is what I do:

First Map F1 to control the rear light

To do it Set CV34=0 default is 2 and Set CV35=2 default is 4

If you want to Dim the front light with F4: Set CV120=32. This is for incandescent lamps. For LED set CV120=160. This will give you complete control independently of the direction of travel. Default for CV120 is 1

If you want to Dim the rear light with F8: Set CV121 to 36. This is for incandescent lamps. For LED set CV121=164. This will give you complete control independently of the direction of travel. Default for CV121 is 2.

This give me independent light and independent dimming of both front and rear light regardless of the direction of travel.

These are my preferences the use of JMRI is invaluable when playing with sophisticated light functions or sound decoders. 

I have a question.  Am I correct that in order to do this process the decoder has to be hard wired, and the front/rear lights need to get wired to different places on the decoder?  I don't think you can accomplish this process if the decoder is plugged into the light board.  Or can it?

Thanks

[jalajoie]

maxman, the above CV values are for 2 Genset locos into which I used an NCE N14IP. 

This is plug and play no hard wiring required.

[cacole]

Something that may be of interest to Proto 2000 purchasers:

A club member recently purchased four Proto 2000 Santa Fe Warbonnet F3 locomotives so he could make an A-B-B-A set.  One A and one B unit have QSI sound, and the others just had the usual 8-pin and 9-pin decoder sockets.

We installed TCS T-1 decoders into the additional A and B units, but the lighting didn't work right in the second A unit when it was set up to run in reverse as part of an advanced consist.  He wanted the number board lights to come on and for the headlight to comply with Rule 17. 

The TCS T-1 decoder handled the Rule 17 programming with no problem, but no matter what we tried we could not get the number board lights to come on even though the documentation indicated that they were wired to the headlight function. 

I switched out the T-1 for a TCS T-4 decoder and discovered that the F1 button would turn on the number boards, but this is the bell function for the lead A unit with sound and when consisted the number board lights came on only when the bell was ringing in the other A unit. 

By remapping the T-4 decoder's F1 function CV from a value of 4 to a value of 1, the number board lights now come on with the headlight, so it appears there is a mistake in the P2K documentation provided with the locomotive.

[rrinker]

 Clearly NOT wired to the headlights. Probably they intended to do that then for some reason they changed. Do the QSI A units do something with the headlight and number boards where one stays on while the other goes out under certain conditions?

 At least they didn;t wire the number boards across the motor like they did in the GP38-2's.

                   --Randy