Help understanding DCC

Hi again,

I have some general questions about DCC: Do DCC-equipped trains work on non-DCC layouts? I would anticipate that they work just like a regular style train, but I'm not sure. Likewise, will non-DCC trains work on DCC layouts, just without the digital controls? I do not have DCC today, and would like to invest in a nice steam engine as a Christmas present from my wife (yes, I always pick out my own gifts! :-). Is it possible to be a good quality engine that would work on a regular track, and then upgrade it (easily) to DCC sometime in the future? Any recommendations on a manufacturer?

Thanks!

Reply to
john
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Hi John.

The fundamental difference is that on a DCC track there is a constant voltage, the DCC-commands are "superimposed" on that voltage, ant the train uses power from the line as the received commands tell it to do. On a "normal" track, the voltage varies with turning of the vontrol, and tran speed accordingly, and there is no control signals on the voltage.

DCC-trains can, in certain cases (the DCC chip should be "told" with a jumper about the situation) run on "normal tracks", but "normal" trains cannot run on DCC-tracks, because the constatn boltage - i.e. they would run at full speed all the time.

my 2 cents Thomas

snipped-for-privacy@jebeck.com wrote:

Reply to
Thomas

Only if they are equipped with decoders that automatically sense the power type, and switch modes.

No.

Yes. Most current production includes a PC board with plugs so all you have to do is plug in the decoder. But some "DCC Ready" locos would require soldering, and some are DCC ready only in the sense that a decoder could be installed, if you know what you're doing, which your questions suggest is not the case with you, yet. Kalmbach's recent release DCC Made Simple will get you started.

It's also possible to buy engines with DC-detecting, mode-switching decoders built in. BLI makes such, among others. Go to a real, physical hobby shop for advice and information - but do them the courtesy of buying your gift there, instead of looking for a bargain on the web after getting information from them for free. It also helps to find fellow modellers, and ask them for help. They might even invite you to try their DCC locos on their layouts... :-)

If you haven't checked the prices of "good quality" steam lcocos lately, be prepared for wallet shock. :-)

You're welcome.

Reply to
Wolf Kirchmeir

I have a silly little DCC question, this seems as good a place as any to ask:

You put in the address to the locomotive, then turn the throttle to get it moving. Now you want to switch to another locomotive, so you put in that address. Does the first locomotive continue to move at the last throttle setting? Or do you have to use the digital "speed steps" to let the other loco run while you work with another? I think I read that you have to lower the throttle to zero before you switch to another locomotive, is that correct (which would mean you have to rely on the speed steps to run more than one loco)?

I have a fair amount of documentation on DCC, but oddly this has never been clear. I have a Digitrax Zephyr that I bought to switch over to DCC with, but then my layout met its end and I never got to use it. I'm planning to use it with my next layout, which I'm about to start the benchwork on (bought the lumber over the weekend).

Reply to
iarwain_8

Reply to
Charles Kimbrough

Whether a DCC-equipped loco will work with DC depends upon the setting of CV (configuration variable) #29. The default setting is that it will work with DC. Most DCC systems can control one analog engine. Whether an engine is compatible with DCC depends upon the design of the engine; some are, some aren't. There's a good on-line DCC primer at:

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Bill McC.

Reply to
Bill McCutcheon

Actually, that power current is AC, not DC: The decoder erctifies the current as well as controlling its (average) voltage. And ordinary DC loco will just sit there and buzz.

The converse is not true: a DCC loco can run on a traditonal controlled-DC layout, but it must have a decoder that can detect that fact and adjust its mode accordingly.

HTH

Reply to
Wolf Kirchmeir

i> I have a silly little DCC question, this seems as good a place as any i> to ask: i> i> You put in the address to the locomotive, then turn the throttle to get i> it moving. Now you want to switch to another locomotive, so you put in i> that address. Does the first locomotive continue to move at the last i> throttle setting? Or do you have to use the digital "speed steps" to i> let the other loco run while you work with another? i> I think I read that you have to lower the throttle to zero before you i> switch to another locomotive, is that correct (which would mean you i> have to rely on the speed steps to run more than one loco)? i> i> I have a fair amount of documentation on DCC, but oddly this has never i> been clear. I have a Digitrax Zephyr that I bought to switch over to i> DCC with, but then my layout met its end and I never got to use it. i> I'm planning to use it with my next layout, which I'm about to start i> the benchwork on (bought the lumber over the weekend).

I believe what happens is that the command station (the stationary unit, not the handheld unit) 'remembers' these settings (throttle settings). The command station sends messages to the decoder(s) down the power bus to the booster unit(s) periodically, which in turn place these message packets on the power bus (tracks). The handheld unit sends changes to the command station, as you make them. Since the throttle settings are always in digital form as far as the decoder is concerned, I'm guessing that the 'analog' DCC handheld units (the ones with rotary throttle knobs), are converting the rotation to digital speed steps somehow -- much like a joystick, trackball, or (computer) mouse.

i> i>

\/ Robert Heller ||InterNet: snipped-for-privacy@deepsoft.com

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Reply to
Robert Heller

Yep, that's correct, sorry, I assumed everyone runs AC locos like me=20 (Marklin) :-) But for AC locos my proposal is true.

Quite so; that goes for AC-systems as well, an DCC equipped loco can run =

on "standard" controlled AC or DC rail, so long as the decoder is told =

so (by a jumper on Marklin and other ways on other brands). For DC locos =

thats possible, since they, as you say, rectifies their current before=20 using it, regardless of control system. Even an AC loco would run on an=20 DC-track f=F6r that same reason. Only problem there is the 3-rail system.=

It seems to me that the most feasible solution for our friend would be=20 to buy himself a DCC controlled loco, the decoder of which can be=20 "told", in one way or another, to run on conventionally controlled rail=20 systems. Then he can convert to DCC when he likes.

cheers, Thomas

Reply to
Thomas

Thanks for all the help guys. Can anyone recommend a specific DCC-equipped engine (preferably steam) that would recognize it was running on a regular DC track and not need jumping, soldering, etc. - kind of just "plug and play"?

Reply to
john

Must be something about htis thread I don't understand.... I have a DCC controlled layout. (Digitrax). I also have several non-DCC equipped locos, that run quite well on this system, only have to use address "00" and can only operate one non-DCC loco at a time. I can run several decoder equipped locos and a non-DCC loco at the same time.

I have several small IHC locos (steamers) that I have installed decoders in with no problems. They run great, as long as the wheels and track are kept clean...

(my 2¢ worth)

Reply to
Roger King

DCC was intended to be able to operate one DC (analogue) along with as many DCC decodered locos as you have. The 'problem' is that it does this by extending the AC signal on either the positive or negative side so the loco "sees" circa 22 volts AC with bias. Big motors are fine as they can disipate the heat that the AC voltage creates but little ones (N gauge) tend to smoke and burn. Middle sized motors tend to get very hot. If the motor is mounted in a big metal block it would probably be ok. The IHC ones are probably mounted in plastic, so let us know how many hours they take to burn out! =8^D

Regards, Greg.P.

Reply to
Greg Procter

I beg to differ! SOME systems (including all Digitrax and IIRC Lenz units) will allow you to run ONE locomotive or group of locomotives that don't have a decoder under address "00". I was doing just exactly this earlier tonight... several locomotives under DCC control, and one analog locomotive under independent control. The analog locomotive can even be part of a command station (What Digitrax calls a 'UniVersal') consist. However, _every_ locomotive without a decoder will respond to these commands - so they all have to be in the same consist.

Reply to
Joe Ellis

Once a loco is equipped with a decoder, you should never have to "jump, solder" or etc. (unless the decoder fails and you need to install a new one). Many manufacturers make decoder-equipped engines; probably all come set to default to DC when there's no DCC. If they aren't so programmed out of the box, CVs are changed by reprogramming the decoder electronically, not manually.

I suggest you check out the on-line primer I recommended in another message in this thread.

-- Bill McC.

Reply to
Bill McCutcheon

Hi Bill,

Thanks again for the help. I did read the primer you posted earlier. I apologize for not being clear with my question. I wasn't able to tell from the on-line primer if ALL DCC-equipped trains would recognize that they were running on a regular track without programming, or if just some brands of DCC decoders could tell automatically, and some could not. If that were the case, I was asking if anyone could recommend a specific brand of engine that would know the difference. Seeing as my setup is not DCC equipped now, I would lack any of the equipment necessary to program the engine to do anything. Is there a way to tell when purchasing an engine if the decoder is set to "default to DC" on a regular track, or am I just taking a chance and hoping that the assumption is correct? Will I do any damage to the engine if its not?

By the way, someone made a suggestion about visiting the local hobby store. I actually tried that prior to posting here. My LHS is an "Allied Hobbies", and the person behind the counter made it clear that he "knows nothing more about trains then what is written on the side of the box". I'm sure that there is a better train-oriented hobby store around - I just haven't found one yet. I did go to an open house for a Model Railroad club this weekend, but nobody had the time to talk to a newcomer. The women working the desk couldn't even tell me when the next meeting was, or how to become a member (not sure why I would want to). I've been building and flying rc-planes for about 10 years now, and if I have learned one thing about these "specialty hobbies" is that it is very hard to get started in if you don't have someone that can "mentor" you. I didn't grow up around trains, so this is all new to me, and I'm finding it tough to get real basic info - most of the stuff I'm finding assumes some level of knowledge that I just don't have yet...

Reply to
john

I believe that all decoders include analog mode conversion (DC operation) and come with that feature set to "on." The one loco I bought with a decoder already installed (an N-scale Atlas with Lenz decoder) certainly came that way. The easiest way to check is to put it on a DC track and try it. Take your business to a hobby store with a test track or one that agrees to a 24-hour return so you can try it at home. I don't think you'll do any damage by putting a DCC-only engine on a DC track.

-- Bill McC.

Reply to
Bill McCutcheon

Better get a refund, then...

As I said in a previous reply to Wolf, analog locomotives CAN run on digital track on some systems - Digitrax for sure, and Lenz as well IIRC.

Yes, there is "AC" on the rails (though it's not REALLY AC...). However the systems that allow running analog on the digital system introduce a 'bias' into the "AC" signal, providing more time at peak voltage on one side that the other. This allows the motor to begin to turn in that direction. The longer the biased pulse is stretched, the more current in that direction, and the faster the motor turns.

An analog locomotive 'sings' on a digital track - the result of the core of the motor moving rapidly back and forth at the DCC pulse frequency. As the bias is introduced, this 'singing' drops in pitch and volume as the analog locomotive gains speed, a clear indication that the frequency of pulse is changing.

Now, this increase in the pulse length of the DCC signal can significantly increase the length of time it takes to transmit DCC commands to other _digital_ locomotives. In fact, most clubs prohibit use of analog locomotives (and the capability _can_ be 'locked out' on Digitrax systems) because it can make operations very difficult - an analog locomotive running near full throttle on a digital layout can mean time delays of a second or more, depending on how much DCC signal traffic is being generated.

Reply to
Joe Ellis

Wow! Well shut my mouth! I didn't know any of this, I will keep a close eye on the heat situation. I have not noticed anything unusual to date, though. thanks for the information...

Reply to
Roger King

Horsehockey. But then considering the source...

I have several N scale analog locomotives that have run hour after hour on DCC with no ill effects.

The only thing you have to be concerned about is the "coreless" type motor. They _can_ overheat when run decoderless on DCC, since they don't have the metal core that serves as a heat sink... and you can find these in any scale, usually on remotored locomotives. Very few companies use them as OEM motors.

Don't bother, Greg - the only time I see anything from you is when it's not from you.

Reply to
Joe Ellis

Read the above again - keep rereading it until you get a clue.

That's ok Joe - you got the coreless motor problem totally wrong, but as I know absolutely nothing ... Never run coreless motors on pulsed power because each pulse is high current for the type of brushes employed and shortens the motor life drastically.

Regards, Greg.P.

Reply to
Greg Procter

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