Author Topic: CV's for ESU decoders in IM SD40-2's  (Read 720 times)

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squirrelhunter

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CV's for ESU decoders in IM SD40-2's
« on: September 12, 2018, 11:49:28 AM »
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I am "hard" permanently consisting a few ESU equipped SD40-2's for trainshow use. Does anyone know what the CVs are for the following settings?

Change direction (run reverse/forward)
Turn off headlights
Turn off front headlight
Turn off rear headlight
Make headlights directional

Thanks!

jdcolombo

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Re: CV's for ESU decoders in IM SD40-2's
« Reply #1 on: September 13, 2018, 12:20:26 AM »
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You really need JMRI or a LokProgrammer to do any kind of advanced programming of an ESU sound decoder.

That said, it IS possible to use raw CV programming to accomplish what you want, but it is dangerous.  One small mistake can mess up the entire programming, requiring a factory reset (at the very least).

Changing direction isn't hard - it requires you to set a particular bit in CV29.  Since I don't know what your current CV29 value is, I can't tell you what value to put in for reverse running.  Read the CV29 value and report back.

When you say "turn off headlights" do you mean program the decoder so that neither the front light and/or the rear light comes on when F0 is on?  If that is the behavior you are looking for, then you can do the following:

To eliminate the front headlight, set CV31=16, CV32=2, then CV266=0.
To elimiinate the rear headlight, set CV31=16, CV32=2, then CV282=0.

Headlights are directional by default on ESU decoders.  Do you want them non-directional?  Which one (front or rear or both)?

Again, I cannot stress enough that using raw CV programming to do these kinds of things with a LokSound is playing with fire.  Find a way to hook a computer to your DCC system and set up JMRI.  You'll live longer.

John C.


squirrelhunter

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Re: CV's for ESU decoders in IM SD40-2's
« Reply #2 on: September 19, 2018, 01:32:16 AM »
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John,

Thanks for the reply! These are train show runners, so beyond getting them to run in the right direction and have their headlights operate correctly, I'm not doing any other programming at this time- although an NCE USB interface is on the to do list for future DCC programming.

I wasn't able to get to these before the show last weekend, but I'm hoping to work on them this weekend, so I'll report back on what my CV's are set to and how it goes

squirrelhunter

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Re: CV's for ESU decoders in IM SD40-2's
« Reply #3 on: November 11, 2018, 08:14:16 PM »
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John,

I was finally able to get around to doing the programming I asked about. The consist is 3 units, 2 facing forwards and 1 backwards. I used your instructions, and now only the front headlight of the 1st and 3rd units comes on- so that is a success. I really wish I could just use consisting to get the necessary effect, but just this year these units have run on layouts at shows with Digitrax, NCE and Easy DCC, which is why is just gave up and "hard" consisted them together.

On CV29, they all read back as 46, and I found something online that said to flip the direction, simply reduce the CV29 value by 1, which worked for getting the rear unit to run "backwards"