Page 18 - November December 2016
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you off trying it. Using smartphones – or old iPod Touches - as throttles with DCC is getting commonplace at exhibitions.
Programming Options
Programming decoders is something you will have to learn to do, but it is actually quite simple and straightforward.
All decoders keep operational parameters - their address, for example - in what are called Configuration Variables, or CVs. Other uses for CVs is configuring the lighting functions, tweaking the loco motive’s top speed, or fiddling with sound volume settings. Programming isn’t a good term for the process of setting a value into a specific CV, but that is what it is. Different systems offer different ways of pressing the buttons to do this, and some are easier than others. You’ll tend to find that the more advanced systems have the simplest decoder programming processes, too.
There are two basic methods of programming decoders; Service mode, which uses a special program track, and Ops mode. Service mode writes, and reads, programming data to whatever decoder - loco - is on the program track. Your chosen system should support Service Mode, with both Page and Direct service mode programming operations.
Ops mode, or Programming on the Main, allows you to change the values of CVs in a specific loco while it is running on the layout, but does not support read-back. Ops mode is vital these days for such things as fine tuning decoder operational values, and setting sound volumes, so again, make sure that your chosen system supports it.
The system should support a separate program track for Service mode programming . Anyone who owns one of the few systems left on the market that does service mode programming via the track outputs - aka Broadcast Write - will tell you that they have programmed all the locos on the layout to the same address, more than once. If they don't own up to it, they're either exceptional people, or liars. Digitrax Empire Builder users, own up here!
Power capacity
Next, Look at the overall power capacity of the individual boosters. We mentioned this above. If you plan a layout that has three HO locos and no more, then a modest system that can supply 1.5 or 2 amps and support two handheld throttles may well be all you need. HO scale, again, but a two-deck layout filling a single garage, with maybe 40 sound-equipped locos, however, will stretch a single 5-amp booster and is likely to require two or even more, each powering part of the layout. In O-scale, where Atlas diesels have two motors in them that can draw two amps together in normal operation, and possibly 4 or more under stress, may well mean multiple 5-amp boosters on even a relatively modest layout. And remember, too, those O-scale locos won't necessarily be running at their best on your existing 1.5amp DC system!
Make sure too that the system supports accessory decoders if they're in your future. All larger systems do, but some entry level and trainset oriented systems don't. Accessory decoders are used to operate points and signals and almost anything else that can be worked by the movement of electrons.
How to Buy
Above all, don't buy blind, and don't buy down to a price. Work out what you want to do, research different systems in that capacity range via the internet, friends, and the NMRA member aid process. Consider the choice factors that I’ve outlined in the last page or so, and spend some time looking at manufacturer web pages. You might even buy the odd book or two, and I’ve listed a couple below in the resources list.
Don't be afraid to ask dealers dirty questions about how the system works and how you use it. Ask to play with it, use the throttle and run a loco up and down. Check how the functions work and what the
throttle display tells you. Ask about operating accessory decoders and about programming. If he can't answer them before you buy, just remember that means that he won't be able to answer them afterwards, either!
One last tip: when you've bought your system and got it home, resist the temptation to connect it to the layout straight away. Instead, get it out on the dining room table with a yard of track and a loco with a decoder in it, and explore it there. Understand how it connects to the track, what the displays on the throttle and any lights on other boxes mean, and how to select and run a loco. Only when you're familiar with how it works and how you make it work, should you start to connect it to the layout.
But before you do that, you need to have a locomotive with a decoder in it, to be able to run on your layout. And a layout that’s powered by the DCC system. We’ll look at those next time.
Further Resources
 NMRA Member Aid. Don’t forget that the NMRA actively encourages members helping members and sharing knowhow. I’m the member aid contact for DCC and Sound.
 Manufacturer’s web sites. Digitrax, NCE, TCS, Soundtraxx, ESU and other DCC manufacturers large and small have extensive websites with downloadable documentation for their products.
 Yahoo Groups: there are yahoo groups open for most of the major DCC manufacturers.
 Other NMRA members and other modelers who’ve not seen the NMRA light yet. Don’t hesitate to ask other DCC users about their systems and preferences.
 NMRA Standards documents. Hugely technical specification documents. Don’t bother.
 JMRI.Sourceforge.Net: Homepage of the JMRI/DecoderPro project. It also contains a wealth of information about connecting computers to DCC systems, and is the “server” component for WiThrottle, EngineDriver and Digitrains smartphone/tablet apps.
 Books
 The Digitrax Big Book of DCC is available as a download, but
I’d hesitate to pay for it these days as it is now very dated. The technical explanation as to how DCC works is however good, and still relevant.
 The Comprehensive Guide to DCC, another early book by Stan Ames, Rutger Friberg & Ed Loizeaux. Also very dated.
 Aspects of Modelling – Digital Command Control, by Ian Morton from Ian Allan Publishing, 2007. OK, but a little too simplistic, and now also getting dated.
 Digital Command Control for Railway Modellers, Nigel Burkin/Crowood, 2008 or 2011 editions. Good, not too basic, less dated.
 





































































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