I have some jargon for you that I am confused about. In the first comparison table in the first two rows, it refers to "maximum number of cabs" and "maximun number of locomotives to be controlled". What is the difference and why is this important?
The first value always seems to be the same or lower than the second value.
There is no relation between "maximum number of cabs" and "maximum number of locomotives to be controlled"
The cab is the controller, fixed or handheld. Each cab can control multiple locos - either by switching between locos using pre-assigned buttons or by calling-up the loco in the normal way.
Sometimes it is helpful to have a number of cabs so that you may use a separate cab for separate locos running on the layout. Also, you may wish to invite your friends around to run the layout together. It's great to give each driver his own cab.
Now I understand. For "cab" read locomotive control unit. And a control unit (cab) can control many locomotives. So you could have once "cab" controlling the main line operated by the father, for example, and another "cab" on an extension down the line controlling the sidings and operated by the son. The new Gaugemaster Prodigy Advance system has this cabability.
Now the next bit of jargon is "mu capabilities". When I see this what does it mean and how important is this feature in a system?
DCC systems offer three choices for consist control:
The Basic Consisting method is to reprogram all the locomotives in a consist to the same address and run them on one throttle. In this case all the locomotives must be headed in the same direction, head to tail, head to tail, head to tail.
Advanced Consisting stores the consist information in each decoder that supports this feature. The locomotives can be added to and deleted from the consist in any orientation head to head or tail to tail.
"Universal" Consisting stores the consist information in the command station and allows you to consist locomotives with any DCC decoder as well as an analog locomotive in any orientation.
This is a big deal in the US. I think less so in Euro.
Lenz developed USP because it is needed on their systems, both the set 90 & set 100 cut the power to the rails at regular intervals. The USP was developed to prevent any running problems from the loco's having no power or digital signal while the track power is off. They still haven't developed a fix for LED's and lamps blowing from the spikes when the system powers up again.
On other systems USP does provide the advantage of being able to run a loco over several inches of masking tape with it stalling.
Multitraction, or double heading as some systems call it, is not a standard type of MU or consisting, a system which supports this is quite limited in its capabilities, as Doug says it can only handle 4 loco's in a consist.
There are 3 types of consisting which are accepted as NMRA standrards:-
Basic consisting; this is where any number of loco's are programmed to the same address, all systems support basic consisting. It is however not very practical, as it requires decoders to be reprogrammed before and after running them in a consist.
Universal Consisting; with this method you enter the addresses of the loco's you want in a consist and the command station will remember them, and send commands to all loco's in the consist. The limiting factor here is the max loco's the system can handle, as if the system can handle 10 loco's and you have 9 in the consist only one other loco can be run at the same time.
Advanced Consisting; with this method you enter the addresses of the loco's you want in a consist and the decoders will remember they are in a consist and will respond to the "consist address". There is no limit on the number of loco's you can include in a consist with this method, if you have 10000 loco's you can put them all in a consist, even if your system can only run 10 loco's you can still have a consist of any number of loco's and run 9 others seperately!
That just about covers that bit of jargon although the word "consist" is used a lot.
Looking at the various tables again we come to the area of speed control.
Its seems to be full of knobs, pots, keypads and sliders and any combination.
Firstly, how does a "pot" control speed and direction?
And what is the difference between a "dial" and a "knob"? Or are they the same?
Whilst I understand what a knob might be (you turn it?), a keypad (you press a button or a key?) or a slider (you slide a lever up and down presumably), where there is a combination listed does that mean I have an option of using both, either on its own or in tandem with the other?
And then we have "speed steps". Now the more "speed steps" the better I take it. If this is the case then why would anybody want an option to use 14 "steps" if 128 are available? I don't understand this.
Its not really a question about jargon here but more one of clarification.
But then we come to "functions" with various numbers. What is meant by this and what other type of language is a sales rep likely to use when selling "functions" to me?
Consist & MU/Multiple Unit are one and the same in DCC talk, basically couple several loco's together and you have a consist/multiple unit.
With speed control knob and dial are one and the same. A pot which is short for potentiometer is what the knob actually turns, this gives an arc of around 270 degrees from stop to full speed.
The better throttles don't use a pot, instead they use a rotary encoder, but still with a knob. A rotary encoder has no physical end to it's travel, and so it can take several rotations from stop to fullspeed, this gives much finer speed control.
My system uses rotary encoders, and I have one loco that takes around 30 sec to move from one sleeper to the next at the slowest speed setting. Control like this isn't possible with a pot.
Some systems use both knobs and buttons to control speed, depending on the system you may be able to use one or the other, or you may be able to use both.
Speed Steps are literally the number of steps between stop and fullspeed, there are 3 modes of speed steps 14, 28, and 128.
14 steps is the original standard and was all we had when DCC first came out, this was later increased to 28 to allow better control, this has now been extended to 128 steps to give the ultimate in fine control.
14 steps is the baseline standard, all systems and decoders must support this to be compatible with each other, 28 & 128 steps is a recomended practice, systems and decoders are not required to support 28 or 128 steps, but is recomended that they do.
By ensuring that all systems and decoders are compatible with 14 steps loco's fitted with an old decoder can be run on any system, while an older system can be used to run loco's with modern decoders.
This is "backwards compatibility," and ensures that all DCC systems can work with all DCC decoders, regardless of make or age.
Functions can be what ever you want them to be, that is the idea of them. Functions can be used to control lights, sound effects, or even mechanical devices such as uncoupling, and doors on carriages.
There are currently 13 functions, F0-F12, however there is a proposal to extend this to 19 functions F0-F18.
The only standard function is F0, this is for forward and reverse headlights, all decoders and systems must support this function. With this function you can turn the headlights on or off by pressing the F0 button on a throttle, also whether the forward or reverse headlight is lit is determined by the direction the loco is travelling in, even when the loco is stopped the lights will remain lit depending on which direction the loco is set to.
Functions F1-F12 are recomended practices for systems, they don't have to support these functions, but it is recomended that they do. Some systems support all of these functions, others only a few of them, while some basic sets only support the standard F0.
What you do with functions is entirely up to you, for some loco's you might not want any functions, just speed and direction, or you may want some special effects to make your model more realistic. You can also buy function only decoders, these don't have controls for a motor, and so are mostly used in carriages and wagons for lighting, opening doors and such.
Some possible uses for functions are
1. individually controlled marker lamps
3. sound effects such as whistle/horn, couplings clanking, brake squeal, etc.
4. opening doors on carriages or multiple units
5. smoke units
6. working fans
7. anything else you'd like to add to you models
Also sound decoders which fit inside a loco use these functions to control specific sounds, as well as the chuffing or motor noise which is synchronised to the loco's speed, and because power is supplied even when the loco isn't moving you can activate these sounds at any time, such as sounding the whistle before departing from a station.
On rotary encoders: Yes they are better as when you switch between locos, you pick up the current speed of the loco without any problem. Your LCD read-out displays the speed of the new loco and the rotary encoder allows you to increase or decrease from that exact point.
Compare this to the ZTC 511 system that has a linear (albeit on an arc) controller. When you switch between locos, there will be an adjustment required to synchronise the controller with the current speed.
Its all gradually becoming clearer now. I trust DCC newbies and wanabees are learning as we work our way through the jargon.
Continuing through all the tables we next come to following terms:-
Operates stationary decoders
What is feedback? Some systems have it and some don't.
And the software upgrade thing. Does this mean I need a computer to hook the DCC up to or do you get plug in modules to upgrade the unit? Manufacturers obviously go through a process of ongoing development of a product presumably. So if a system offers software upgrades is it effectively future proof in that a whole new system does not have to be bought to benefit from new "must have" developments?
And finally for this session what is a stationary decoder and why do some systems operate it and some don't? If it is what I think it is then I am puzzled by this but then my thinking is probably wrong (it normally is when it comes to DCC!).
I am assuming that a stationary decoder refers to a loco that is stationary that has a chip on board.
OK I'll start with software upgrade, generally the system manufacturer will provide a chip which replaces the one currently in the command station. Fitting the new chip can either be done by the user, or by a dealer/service agent. The new chip is already programmed with the new software, so you just unplug the old chip, plug in the new one, and go back to running trains.
There are 2 types of decoder;
1. Mobile decoders, these are the ones fitted in a loco.
2. Stationary decoders, these are generally fitted under the baseboard and are used to operate points, signals, or other effects such as level crossing gates and lights or any other device you want to control from your throttle.
Feedback allows devices such as a stationary decoder to report back to the command station, this infomation can then be displayed on throttles or a computer screen.
For instance a stationary decoder might report back which route a point is set to.
Feedback is also used for block detectors, a block detector can sense when a loco enters it's section of track, using feedback it can then tell the command station that a train has entered it's block.
Used simply like this feedback allows the operator to see what is happening on a layout without actually looking at the layout! For instance you could change a point which is hidden in a tunnel or at the other end of the layout, and you can be certain that it has changed because it has told you so.
However feedback can also be used to affect other devices on a layout automaticaly, some examples are;
1. When a loco enters a block the block detector can tell a signal that it needs to change to red, or it could tell the level crossing lights to flash or the gates to close.
2. When a point is set to the right hand track it can tell the signals to show a red aspect for the left hand track.
3. You could use a block detector to sense when a loco is passing through a set of points, it can then tell the points not to change while the loco is passing through them.
4. Anything else you can think of.
However there are three expressions used towards the end of the table:-
1) Auto Shuffle Train/Signal Speed Control
2) Loco Number Readback
3) CV Readback
Now I suspect that CV is Control Value which is the number assigned to a chip I believe. Is CV Readback the same as Feedback that we discussed earlier?
Or is this Loco Number Readback?
You can see that some expressions used seem to suggest the same thing although clearly they don't.
And the Auto Shuffle Train/Signal Speed Control I take to mean that a loco can be set up to automatically reverse although it could be something linked to the automatic stopping and starting of trains and the control of related signals.
So clarification here please would be appreciated.
PS at this topic is seen to draw to a conclusion I will, in my own simplistic way, attempt to summarize the meaning of the jargon. If I have a go at this then at least it will prove to myself that I understand!
CV is short for Configuration Variable, decoders have over a thousand CV's which define how it is configured, or rather how it responds to a command given from the throttle, and can all be altered by the user to alter the performance of each decoder, and therefore each loco.
Most of these CV's the user will never need to change, some they will, some can be adjucted if you wish. I'd put CV's into 4 categories, of which only the first category must be changed, the rest can be done if you want to change how your loco runs:-
1. Identity CV's, these determine the loco's address, and therefore must be differant in each loco. All decoders are supplied by the manufacturer set to address 3, this can be changed on all systems, and usually quite easily.
2. Running CV's, these determine how the loco runs, adjustments such as maximum speed, starting voltage, and mid point voltage can be set with these CV's. As an example a tank loco could be set to have a low top speed so it is more contollable at shunting, while a loco that needs a lot of power to get started could have it's start voltage increased so that it starts as soon as the throttle knob is turned. You can also set up acceleration and deceleration rates so that a slowly speeds up or slows down.
3. Function CV's, these allow you to adjust how a function performs, for instance you might want a light to flash when you press a certain function button on your throttle, you can do that with these CV's.
4. Hidden CV's, these are simply CV's that will you will probably never need or want to adjust, or they could be inactive in certain decoders, or even read only CV's such as the manufacturer ID which all decoders have set in CV08.
So what is CV Readback? Well quite simply it means a system can not only set a CV value, it can also read what that CV is already set to in a decoder when the system is in programming mode.
Loco number readback is similar, except it means a system can read a decoders CV settings while the loco is running, not just while programming. This is becoming more widely known as Bi-Directional Communication, in other words the system is talking to the decoder and the decoder is talking to the system.
Auto Shuffle Train/Signal Speed Control, is wher a system can tell a train what to do automatically, without any input from the user. For instance if a signal is red, the system might tell any loco approaching that signal to slow down and stop, then when the signal turns green the system will tell that loco to gradually accelerate till it reaches it's original speed setting. Or it could tell a train that has reached the end of a branchline to stop, wait a few minutes then accelerate back in the opposite direction.
1. If the table says that I can run a non decoder equipped loco does this mean that I can run all my existing fleet chipping only those locos that I wish and using the DCC controller as an analogue controller for those non chipped locos? I guess that the fixed DCC track voltage would cease to exist when a non DCC loco was being controlled. This would mean that I could only have one loco controlled at once if a non chipped loco was involved and non chipped locos would need isolating before a DCC equipped loco could run. Correct????????
2. Advance consists. I understand the idea but cannot see this as a base station only problem. I would have thought that recognising consists in this way was more a loco decoder problem than a base station issue. Surely it is the loco that has to recognise the consist number & the controller sends out commands to the consist as a whole with each loco recognising individually that it is part of that consist. The difficult bit is thus in the loco not the base station. What have I missed?
3. Communications BUS. Er yes. Do I really care as long as there is one? Seriously I would like to understand why I should care & why one is the best although I am sure it is not that simple!
4. A computer interface sounds like a wondeful way to get even more confused. I know that ultimately I could let my computer run my railway for me but is this interface of any other use with systems as supplied? Do I need lots of extra - & probably expensive - software to make it useful?
5. Does buying one brand of base station initially bind me to that make for the future? Do accessory controllers, & all the other bits - other than handsets- transfer between base station makes if I wish to change later? It will be a lot less scary if changing base station makes is problem free in a rather fast changing aspect of modelling.
If you have had the patience to get this far then I thank you. If you reply I will be really grateful!
1. You can't have DCC and DC control at the same time. There is nothing to stop you installing a double-throw switch to switch between DCC and DC, but beware of point decoders and other modules if you have them. I don't think they would like DC current fed from the DC controller. It would be best to isolate those too if you have them.
Using DCC, you can usually have one non-DCC loco on the track, controlled with address '0' by the DCC throttle controller.
2. Consists. The DCC controller has to gang the consist locos together so that it can control them with one address. Your consisted locos will then behave as one, called up by any controller on the network by the consist address.
3. BUS. Yes, it's nice to have one so that you may add modules for expansion. I We're talking started with one controller - I now have 5 all linked together and will probably add 5 more if my 'World Domination' plans work out.
4. Computer interface. Remember there will always be people who want this. That's the way it is. I personally think a model railway loco should be controlled with a cab control from the side of the table, but each to his own. I have a computer in my track room, but for the moment it's used to listen to Internet radio. Computers do take the hassle out of complicated and complex layouts. You can program routes, automate sequences and work to schedules that flash up at you - just like they do today in the real railway world. You can have your detailed loco database link up to your control system and using a feedback system, you could theoretically control it from anywhere in the house.
5. Brands. Hornby DCC system and it's XPRESSNET are hot topics right now. This is a communication BUS that is set out and designed to a specific protocol. Other companies' products that also use the XPRESSNET or XpressNET BUS can be theoretically linked together. Companies that use XpressNET include: Atlas, Lenz, ZTC Controls, Arnold, Roco and now Hornby.
Loconet is another type of communication protocol. Loconet and XpressNET are not compatible. Companies that use Loconet include: Digitrax, Uhlenbrock, Fleischmann and a few smaller manufacturers.
Thank you for the reply. It has answered most of my questions.
It appears that there is a common thread of most systems in XPressNet but that each US manufacturer has their own specific & proprietary system. Something to think about as I was contemplating NCE or Digitrax as my preferred system but might now rethink it.
I have posted a follow up question in the XPressNet thread where I hope it fits best.
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