Decoder Programming Tips
For DCC Locomotives

Here are a few decoder programming tips from my experience.  First of all, I am assuming that you know the basics of entering a locomotive address and maybe even how to change the start voltage by altering a simple CV (configuration variable). 

My first tip is to always start on the Programming Track (service mode), especially if you have installed your own decoder.  This is to pass the "smoke test" in case you've done something wrong. 

Recently, I ignored my own advice. I had installed a tiny Digitrax decoder in an HON3 diesel and had tested it on the programming track. Everything worked so I put the shell back on and set the locomotive directly on the mainline without double-checking on the programming track. Zap. I fried the decoder.  Why? Because the diesel shell was metal and created a short circuit to exposed parts of the decoder when I put the locomotive back together. If I had rechecked my work on the programming track I would have saved myself $30 and a lot of aggravation. Lesson learned.

Some command stations on some systems don't use a programming track. In programming mode they shut down the mainline. Check your documentation. I use Lenz and have only a little knowledge of Digitrax although I use decoders from Digitrax and NCE.

Where model railroaders often get in trouble is trying to change things in more complicated CVs like 29 where you need to understand more about bits and bytes. Or do you?

While struggling to overcome my fear I came across a CV29 decoder calculator on the Internet. You click some boxes to choose things like "run on DC layouts" or "change locomotive direction". The calculator tells you what number to put in the CV.

Should you want a comprehensive understanding of DCC, one of the best guides is Allan Gartner's DCC site.

If you're looking for a simple explanation of how to calculate bits and bytes, try Programming Decoders by Stan AmesBoth these sites helped me a lot.

DecoderPro: the ultimate decoder programming tool

JMRI DecoderPro is a free software program. However, you need to connect a computer to your layout. I had acquired a refurbished Dell laptop on eBay several years ago. 

I was using it for the ShipIt program for operations. You don't need a fancy computer. You do need some way to connect it. I needed to install a Lenz LA152 Universal XpressNET adapter to the LENZ LZ100 Command Station and then a Lenz LI-USB interface between the COM1 port on my computer to the LA152.

It also helps to have an Internet connection to the computer. I ran a cable from my router in an adjacent room. I have now found a card to make my old laptop wireless.

Digitrax would have another setup for their LocoNet. I'm unfamiliar with NCE, but NCE follows the same NMRA protocol as Lenz so it should be similar. Again, check your documentation if you're using another system.

Is it worth all the effort? I certainly think so if you have more than one or two locomotives and want to do some fine-tuning or get them working correctly. I completed the setup on a Wednesday in March, 2010. I had a few hours to play with the software before my Wednesday evening operators showed up.

I quickly reprogrammed an old IHC 0-6-0 and a couple of old Atlas diesels that had some of the first generation Lenz decoders hard-wired into them.

One of the first tests that evening was to reprogram several NCE decoder-equipped steam engines that NMR club member Paul Bailey wanted to double-head. This involved experimenting with speed tables to get them to match characteristics. 

I would never have tried to do this without DecoderPro. Then member Doug Tate arrived with a Spectrum 4-8-4 that had a Soundtraxx Tsunami sound decoder that wasn't working. Doug had tried to change some CVs because the engine had lost it's "chug". The bell and whistle worked but not the chug. He had tried to get it working on the NMRC Digitrax-equipped layout without success. 

This may be because we don't know enough about Digitrax yet. We only got it up and running a few weeks ago. However, I quickly found the decoder listed on DecoderPro and did a factory reset on the service mode track and reprogrammed the address from 03 to a four digit address of 3030. 

We set the locomotive on the mainline track and off it went chug-chugging merrily along. Then, in ops mode, while it was running, I adjusted the speed of the bell and volume of brake squeal and the horn. This only took a few minutes to do. 

This was before I did more than glance at the online manual.

Here was my very unsophisticated decoder programming setup.

DecoderPro and computer installed at Utopia.
DecoderPro setup

I keep an HO programming track permanently connected to the Lenz system. A piece of HON3 track is alongside connected by alligator clips because I was installing decoders in my narrow gauge engines.

The LA152 adapter plate has been added behind the computer. It also gives me two more DIN plugs. The rest of my layout has individual DIN plugs in the fascia instead of the adapter plates. The plates provide a neater appearance but I hadn't needed the computer connection. There's extensive documentation for DecoderPro on the Internet. Check out the jmri website if you're interested in doing more complicated decoder programming and have a look at my jmri page.

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