DCC no arguing please ...

Hi folks,
Been reading the various dcc freds with some interest without going down the various merits and demerits path again could anyone enlighten moi - a total
no nothing re dcc whether I understand the following correctly and set me right on a few questions?
Are all dcc built to NMRA standards are fundamentally interchangeable?
ZTC are the only fully British dcc manufacturers (and why are they so damned expensive)?
Single function decoders can only do one thing ... "Make engine go ... back forwards - speed"? ... additional functions (where available) set lights, directional lights, sounds and so forth ...
In essence accessory decoders are simply "on-off" switches - the more functions the more "switches"?
Can accessory decoders (or multi function decoders for engines) be mounted inside stock and used to control coupling - if so any recommendations on coupling system?
Can someone explain "programming" - in the sense of telling a decoder to do what you want it to ... any special equipment required (for basic use) and so forth?
Route setting ... with my dc layout with a flick of a single switch I can set a route for a train to go from A to B via C and D, another flick of a switch and I could set the route for it to come back via E ... well if the layout was large enough to warrant it, and I don't mind miles of wiring. I understand that dcc can be used for route setting ... true/false ... and if so is a computer hook-up required.
How does dcc cope with reversing loops and the like when you have to change polarity?
--

All the best,

Chris Wilson
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Hi Chris,
Chris Wilson wrote:

Yes - and 99% of the time there's no problem.

No, "functions" are additional to controlling the loco's movement. A single function decoder will turn something on/off in addition to the motor.

There are momentary impulse as well as on/off accessory decoders. Turnout operation and light/signal operation.

It is quite possible, but nobody does it (yet) There would be no real problem, but plenty of work, involved in fitting electro magnets and decoders inside wagons etc to lift the coupler hook or loop. The problem would arise in recognising the address of the wagons to be uncoupled. With the horrible British coupler you are going to have to operate both wagon couplers at once at one end only. (it might be like those office double doors that only open one way - on the forth try you finally get it right!)

It varies with each brand of controller/CU. Basically you can set the controller to "programming mode" and then by pushing the buttons in the correct sequence (shades of setting the video clock) you can set different "CVs" for address and function.

It all depends on the system you buy and the computer program and ... Basically "yes" if you buy the system that does what you want/need.

A special module is required which changes polarity when the DCC (AC) signal is shorted by the loco.

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Cheers Greg, ....

mounted
That's a b******r ... I'd have hought that this would be a major selling point ... rather than all that under baseboard stuff. Certainly if you ran perminatly coupled rakes or "half rakes" and you only wanted to couple/uncouple a limited amount of stock.
....

pushing
you can

CVs?
Command values????
--

All the best,

Chris Wilson
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On Sun, 11 Jul 2004 01:06:00 +0100, "Chris Wilson"

Not quite true, Lenz do locos with DCC uncoupling as does one of the US companies but for coaches or wagons you need to do a bit of DIY

Configuration Variables, these are values stored in memory that tell the program in the decoder what to do, such things as the address to recognise, what acceleration and deceleration rates to use, which way is forward, what lights to display for 'Function 1' etc. Setting these variables is what is described as 'programming the decoder'. Keith
Make friends in the hobby. Visit <http://www.grovenor.dsl.pipex.com/ Garratt photos for the big steam lovers.
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...

Cheers,
--

All the best,

Chris Wilson
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Chris,
Just one or two bits that I feel were glanced over...first of all, I would say, if you are genuinely interested in DCC find someone who has a set-up or a shop which demonstrates and have a play, each brand is different, but at the end of the day does the same thing, bit like a car, some makes will suit one person but not another if you catch the drift. Look to see which suits you best.. The consol ZTC (with option of hand held controllers) or Lenz hand units, which again differ. For a starter set, it may be worth looking at the new Bachmann Eezee (as in "easy") set when it arrives. Apparently it will not be the singing all dancing units that other companies make, but simplified for the not so technical... Not that the others are technical after a few weeks trying... Remember when you first learned to use a computer and look at you now? Digressing, as I said see which suits best. At the end of the day, depending on your current set-up, it may not suit or be practical (cost wise) to start. It is always best when starting a fresh I find from others experience and my own. Also look at joining DCCUK on the Yahoo group. Great folk and someone may say, "I live near, come and have a play".
Re the CV's, this can be used to adjust the performance of a loco. Don't worry, you don't have to if you don't want to, many Lenz have preset or default setting so you can build up to this. All they suggest to start with is changing the default loco number from no.3 to either a 2,3 or 4 digit number so you can start running more than one loco! (Most of the time the loco number - CV1 will be the number of your loco if running pre grouping steam i.e 4472, or if running diesels 7672 for D7672 or 322 if locos tops number is 25 322) You can then move on to lighting if you have a loco like the Hornby 50 or Bachmann 37. Do you want to change the lights over with a button (manually) or when you change the reverser to the other direction (automatic) or turn them off? With some lights (if you use say express models lighting kits) you can have 4 functions after the motor control, each set of lights being on a different switch, example funtion 1 head lights/marker at no. 1 end, func 2 tail lights cab, func 3 headlights no 2 end and func 4 tail lamps... You can get decoders with more functions (think up to 6 at the moment?) Not forgetting with the expensive decoders you can even have steam or diesel sound effects as well as the lights. This will range from starting up on diesels to the engine gaining speed when moving, air tanks blowing off and of course the Horn, similar goes for steam, safety valves lifting, taps open, driver shovelling, filling the boiler, blowing the whistle as well as the chuff. The only bit missing is the real steam!
I can't comment on the control of points yet as I have not gone down this route (yet), but it can be done from the controller, but I feel it does rely on memory for which point is what number. It works in a similar way to a loco input the number and then change the function except its left or right (or straight or branch of) instead of on or off.
Some systems will link into computers, either for point control or programming the CV's for speed curves (how quick a loco will throttle up) or braking. I don't feel I need to tell you about the bonuses of more than one loco on a live piece of track, but one thing is nice is a dark room with a shed of diesels lined up with either tail lights at both ends or a headlight on ready to move off!
Finally, function only decoders exist for just lighting etc, so you can turn on and off lights in coaches. This can be set in two ways, either as a whole rake, or even as can be done on the prototype, individual coaches.... as Graham used to say on Blind date - the decision is yours? !
--
Andy Sollis
CVMRD Exhibition Manager
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Chris Wilson wrote:

Give it a go! Assuming you use that British bedhead style coupling I would suggest you remove the loco hooks and work the coupler hooks in the rakes by soldering a paper clip or iron wire running back into the coach (brake end?) and perhaps an old PO 24volt relay coil (high resistance) to lift it. The iron wire would need to be mostly vertical so that it didn't leave the hook permanently raised. Mount the relay coil flat on plasticard pieces on the coach floor so that you can get vertical and horizontal adjustment easily. Mk 2 can be much neater! :-)

"... Variables" - the sort of thing you don't need to know, in the spirit of the new millenium! ;-)
Regards, Greg.P.
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Yeah right ... I'm still trying to finish re-wheeling and get my existing stock using common couplings without changing them all again ... maybe on my next layout though.
....

of the

Goodness me, "variables", don't tell me they're back in fashion, next thing we'll be getting rid of object oriented programming and going back to subroutines a la Star Trek. :-) Perhaps Pritchards Patent Products are the Borg. ;-)
... and thanks for your initial reply.
--

All the best,

Chris Wilson
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OK, here's some answers for you, based on about 6 years of using DCC...

Yes, from the rails to to locomotive. DCC standards specify the signal on the rail and how the decoders respond to it. Therefore, all DCC decoders can be used on a railroad run by any system. They say _nothing_ (by deliberate intent) about how that signal gets there or how the components _off_ the rails interact. This allows manufacturers to innovate and differentiate their products.

Lack of competition at a fair price thanks to tarriffs? Poor business model? Mebbe they're just greedy sods?

Decoders that elementary are rare these days. Look for 128 speed steps in forward and reverse, and at least F0 (headlight functions, directional, and perhaps some basic effects such as strobes or Mars light). A basic decoder with these functions sells for right around $20 US in a size to fit N Scale. (Digitrax DZ series, Lenz 0511). HO sized decoders can be about 25% less.

Additional functions often take the form of more lights, more special effects (alternating ditch lights or strobes, firebox flicker, marker lights), all independantly controlled. Sounds require a dedicated decoder, which are available both with and without motor control. They _are_ expensive - usually around $150 US.

Yes, but some effects are available on some of them, and each function is not necessarily _just_ on-off.

Normally, no, because there's no need to keep under-layout accessory decoders small. DCC uncoupling IS available - even in N scale!. No need to use motor or accessory decoders, there are function-only mobile decoders available for as little as $12 US that can be used for this. I have a Digitrax TF4 function decoder in an N scale caboose to control an EOT and marker lights... all seperately. A quick Google search came up with over 800 hits on "DCC uncoupling".

Programming is simply setting the Configuration Variables (CVs) in the decoder to make it respond in the desired manner. You can set the DCC address, lighting effects, fine tune motor response both in forward and in reverse, create "speed curves" to match locomotives to each other or some arbitrary norm, etc.

True
No, at least not with a Digitrax system. It _does_ require that all the turnouts be DCC controlled. With Digitrax, routes are kept in the Command Station, and triggered with a single input from a hand-held controller.

No problem. There are a variety of units available that automatically detect the polarity in the loop and reverses it. The operation is completely transparent to the engineer, and the locomotive doesn't care about the polarity - that's determined onboard by the decoder.
I'd suggest the Digitrax "Big Book of DCC" for basic reading (uses Digitrax equipment as examples, but gives some excellent background material), also check some of the following web sites:
http://www.digitrax.com /
http://www.ermodels.com /
http://www.lenz.com /
http://www.loystoys.com /
http://soundtraxx.com /
http://www.ttx-dcc.com /
You should find some answers here. These are US sites, but the information on systems is the same.
Have fun!
--

Joe Ellis

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They have a good business model, at least in the short term, they greatly outspend everyone else in the UK magazines (Large 2 page ads when Lenz or digitrax will just be mentioned in some tiny 1/16th page ad. Consequently they get the reviews as well. Also ZTC attend a lot of exhibitions with a big flashy stand. The result is that a high proportion of UK modellers think ZTC is the only brand around and buy without doing a comparison, hence they can sell well at those high prices.
It appears that Lenz and Digitrax sell enough without bothering with the UK so they have not bothered to do the promotion. Even so at the retail level I think Lenz has the most dealers.
Keith Make friends in the hobby. Visit <http://www.grovenor.dsl.pipex.com/ Garratt photos for the big steam lovers.
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Joe,
I'm wearing my fingers out with all the "thank-you's", like Steve's a great reply, thanks. I have visited the various sites you mention but I do like to get the "users" view rather than the salesmans.
--

All the best,

Chris Wilson
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the
total
damned
back
do
if
change
The more well known makes are NMRA compliant. Manufacturers have to submit their products to them for validation and you will often see the 'Choochoo' symbol on some literature.
Why is ZTC expensive? Pass.
Now let us look at the decoder. They all work basically on the same principle whether it is plug'n'play or hard wired. Unlike DC system rectification and TV interference suppression is done in the decoder. Once you have your decoder installed then you program it. This is quite a simple job that takes seconds. You either have a programming track or an isolated siding to be used for the purpose. The isolated siding can be switched back in use when not required for programming. Next with your controller you read the address of the decoder (Lenz as an example use 003 as factory ready). If your installation is not right you get an error reading (Instruction booklets will then suggest what is wrong). You then give the loco an address number within the parameters of the control equipment you are using. These days with modern DCC equipment this is about the only operation that requires a programming track. I use the Lenz LH-100 from set 100 and that has POM (Programming ON the Main ) facilities. This means e.g I can tune up acceleration rates switch on and off lights etc. In my first loco in multiple experiment. I had wired the motor up on one loco with opposite poles to the rest. When started two locos went in one direction the other went the opposite direction. No problem, just select the right Configuration Variable(CV) and invert the reverse function. I did not even have to take the body off!
Decoders can be very basic or quite sophisticated some have a back emf feature to keep the loco at a constant speed (helpful for the Lima pancake motor). There are others that can drive coreless motors. Functions seem to confuse the non DCC user. Appart from the budget decoders most have four A,B,C & D. Those fitted to Lenz are negative pole with a common positive. A&B are often used for directional headlights and can remain directional sensitive (as you wish) and you can turn the lights off when you wish. There is none of this brightening or dimming as you vary the controller on DC. You can also dim the lights in incremental steps as bulbs can get very hot. There are also function only decoders. These are like normal decoders but with no motor function (handy for driving trailers).
I have yet to dabble with points and signals accessory decoders are used to drive them with feedback to report how points lay etc. For route setting my LH-100 will only do it individually (I could get a tower controller if I wish). A lot of users are now doing points and signals via computer interface and there is software on the market to do this. There is even software to programme loco decoders.
Now to your final point, reversing loops. These are wired the same as a DC system to prevent a short circuit. The only restriction is that overhead line catenery must never be used as a pick up as it will either spike or burn out a decoder in a reverse loop situation. As you can control as many locomotives on the track as you like (subject to base station current capacity) do you really want to be bothered with the problems of working overhead lines?
Apologies Chris and others for such a long posting but I have done this to help you. The final word is this, DCC is here to stay and conforming equipment is made to be forwardly and backwardly compatible. Unless you tend to only have a small limited facility layout it is best to go for the top of the range (or near to) control equipment. On DC you require a controller for each line (e.g. a double track layout). Not with DCC you can set your trains away on the main line and concentrate on shunting in the sidings. If it goes wrong like a derailment you press the emergency stop. regards, Steve
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....
Please don't apologise, yours was one of the most helpful posts on this topic I've seen. Looking at (manufacturers) websites is all well and good but the proof of the pudding comes when you have to use the stuff and I'd rather leech of the experience of others before committing hard earned cash.

tend
of
Makes sense.

Well one per moving engine/train perhaps ... I currently have 4 controllers running 2 main lines, a goods yard, an engine shed, fiddle yard, and an industrial yard ... with each controller being able to control at least 2 of these zones, which combined with lots of insulating sections means that I have lots of built in flexibility ... but I do take your point.

goes
Certainly DCC appears very attractive in a shunting/yard type environment when you've got lots of crossing movements and the like, anyway thanks for your excellent reply.
--

All the best,

Chris Wilson
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