DCC for Dummies

[mushroom2]

OK. For us stuck in DC folks, what's a booster and what's the difference between the main and a programming track?

 

[grumpybob]

Hi Mushroom,

that is a good question and my answer probably should end up as a separate thread.

DCC unlike DC has to have a place where an engine that has a decoder installed can be placed so that the special instructions, commonly referred to as "CV's" (configuration Values) that make the unit go, and do all those different things that you may have read about can be programmed into it require a separate piece of track called a "programming track". This section of track has to be completely isolated from the rest of the layout as the power source for the programming comes from a separate feed from the main console. Example: A new decoder has installed in it the defaults from the factory. Unfortunately the address for each new decoder is the same "3". if not changed, then all engines would run as soon as you ented 3 into your cab as the address you wished to run. You use the Programming track to change this value to usually the engine number painted on the side of your engine thus usually making it unique.

The "Main" is the rest of the railroad that is used to operate your engines on. Some minor programming such as speed selection, lighting, Consisting, etc can be done on the main line, but that is dependent upon the age of some of the DCC Systems and the age and brand of the decoders one has in their engines.

Some of the new Sound equipped engines, such as Broadway Limited and Soundtraxx, appear to have more of a power requirement for programming than a standard non-powered equipped engine. The "power booster" we have been talking about here has been developed by a company to give that programing track that extra power it needs in order for the Decoder to be programmed correctly.

In DCC the term "booster is also used when referring to larger layouts where the standard output of a "command station" may not be strong enough to carry a good signal thoughout the entire layout. Basically this allows you to separate the layout into more sections depending upon power requirements.

Hope this helps.

Bob A.

 

[mushroom2]

Good idea on the new thread Bob. I'm starting a new thread for you guys to explain DCC to people like me. I'm familiar with the concept, but I really don't know the technical details.

 

[mushroom2]

So I don't understand why the need for a seperate programming track. I'm assuming that DCC is just a data stream modulated on a carrier frequency superimposed onto the DC supplied to the rails. If so, then what is the difference between the main output and the programming output? And why?
Is the booster just a data repeater, or if you use one do you have to cut the tracks so you have a seperate DC block system? Can it be used either way?

 

[HaggisKennedy]

So I don't understand why the need for a seperate programming track. I'm assuming that DCC is just a data stream modulated on a carrier frequency superimposed onto the DC supplied to the rails. If so, then what is the difference between the main output and the programming output? And why?
Is the booster just a data repeater, or if you use one do you have to cut the tracks so you have a seperate DC block system? Can it be used either way?

The separate programming track allows you to program an individual loco while leaving all the other locos on the main track. Plus, the programming track is of a lesser voltage; if you screw up the decoder installation wiring, the main track voltage will fry the decoder, while the programming track voltage probably will not. And, at $139 for a full-up sound decoder.....

The booster adds about 200mA of current to the programming track signal, so the communications are more reliable both ways.

Here's a link to the booster, from Tony's Train Exchange page:

http://www.tonystrains.com/technews/powerpax.htm

BTW, DCC is supposedly a square-wave form of AC....

Kennedy

 

[abcraghead]

Also, I beleive that if you used the main track to program on, wouldn't every DCC loco on the main track also get programmed? You wouldn't want every one of your Pennsy steamers to respond to one throttle.

 

[grumpybob]

Programming on the main is a feature of many of the larger systems. It has been referred to as 'programming on the fly'. to do so, you set your cab to this category and then you must give it the engine number you wish to program, and then, you would be able to change certain values. Not Engine numbers. So no major runaways. Unless of course you had two engines on the layout with the same engine #.

Several things enter into play here:
1. the Decoder must be fairly new, not sure of the break point on that, but i do know that most MRC decoders and early Atlas versions are not capable of handling this method.
2. Also, if i am not mistaken, neither the Atlas or MRC older DCC systems are capable of handling anything other than Program track programming.

Most Lenz, Digitrax, NCE and TCI decoders work well in this environment.

Bob A.

 

[abcraghead]

2. Also, if i am not mistaken, neither the Atlas or MRC older DCC systems are capable of handling anything other than Program track programming.

I can't speak for MRC, but the Atlas system does not support programing on a track other than a dedicated programing track. I know, as I own this system.

Regarding that, it's not too bad, but if you plan on getting the handheld, just go ahead and get a better system like the Lenz 02, or comparable sets from other makers. It's more bang for your buck once you get away from console style DCC.

 

[grumpybob]

I can appreciate your comments. When i first started experimenting with DCC I purchased an Atlas system because i was basically installing decoders for other people who also had low end systems. Last year i went with NCE and love every minute of it. It is a whole different world.

 

[abcraghead]

Well don't get me wrong, if all you want is one controller and a console style one at that, the Atlas system is a great, inexpensive way to get into DCC. But once you add a $125 handheld throttle, the advantage goes away. The only reason I even *have* the handheld is because the hobby shop that sold me the console goofed and sold me the power supply too for no extra charge, and all at sale prices. So I saved enough by their mistake to get the handheld throttle too. (I was honest enough to contact the store about the goof and they said "just keep it".)

I've never played with NCE, just digitrax and Atlas (which is dumbed down Lenz) and Easy DCC. I like the big throttle and simple controls of the Atlas/Lenz handheld, but the wireless Easy DCC throttles were really handy.

 

[mushroom2]

Can anyone point me to some good technical reference material on DCC? I think I'm getting DCC, command control and some of the older systems all mixed up.

 

[grumpybob]

The book I was first introduced to is Digitrax's Big Book on DCC. It is a bit biased, and it definitely is out of date, don't really know if an updated versions is available, and I really haven't seen much on the market place any newer.

However, it might clear up the differences you might have regarding DCC and some of the older systems. Although I am not sure what the reference is to older systems?

 

[greffern]

Go ands search on the name: Rutger Friberg. He got some books 'bout DCC.
BIG GURU
A swede that writes in english too.

 

[mushroom2]

Thanks for the input. I'll be checking on those books. I've also been poking around the NMRA standards pages, which has helped some as well.

Bob, the older systems were those like ASTRAC which I remember from way too long ago. Being strictly DC and only dealing with DC people, I had all the systems filed in my head as "remote control". Now with DCC taking off big time, hearing about the command control lawsuits, all the "remote control" stuff has to be refiled into something that I know what the difference and capabilities are of the systems so I know what the heck someone is talking about. In other words is time to keep up with the technology .

 

[grumpybob]

I know what you mean. I went from Conventional DC with 6 cab system to Dynatrol to DCC. Talk about confusion. Recently i re-wired my layout to get the rid of the spagetti wiring i had below. I nearly filled a barrel with it all.

 

[elythomaslumber]

Best web-page and infos I found here: http://www.wiringfordcc.com/

Hartmut

 

[mushroom2]

Great site. Thanks.

 

[CBCNSfan]

OK, question. So far all my layout wiring is for DC. Now from reading posts and seeing all the adds from different manufacturers offering their products and what I'm hearing about DCC seem's almost too good to be true. Right now I guess I'm begining to look at DCC mor seriuosly, so my question is are all the DCC products from these different manufacturers compatable. Like if I purchased a complete set from mfg.#1 and at a later date mfg.# 2 came out with a good deal on the loco decoders would they work ok with the set from mfg. #1

 

[elythomaslumber]

I never had any problem using equipment from different manufacturers. I use a simple beginners system (Uhlenbrock Daisy) which handle DCC and Maerklins Motorola II protocol at the same time without disturbing each other! Also I use decoders from ESU, MRC, Kuehn, UMELEC, QUANTUM-Sound, CT-electronics, Maerklin, ATLAS and TAMS and the same time. The only thing you've to attend is that more or less all system components have more or less features. That means for example that my central DCC system can handle only 5 functions but some decoders have up to 12 functions. Also my system can't perform a read-out of CV values from decoders. Maybe also some central DCC systems can't handle very old decoders with register programming but these decoders are non more in production. So finally I can tell you I never had any problem with compatibility!

One thing you've to keep in mind is if you want to control other equipment like turn-outs, signals, uncoupling devices,...
There are some different standards which have nothing to do with DCC. That means one manufacturer of DCC system use the "S88" bus, one other the "Loconet" or the xpressnet and so on.

Hartmut

 

[CBCNSfan]

Thank's elythomaslumber, I imagine that DCC will be the next thing on my list of what to get, and if past history is any indicator of how I'll do it, an entery level set will be purchased and added to at a later date. Life's like that eh!

__Willis___CB&CNSfan