Goods yard controls

[Graskie]

If the layout is not too big you shouldn't need a booster, nor separate sections for individual DCC loco control, WTD.

I understand what you mean by positive DC control of up to 4 locos at the same time, with 4 individual control knobs on the same controller,

 

and to do that effectively on a DCC system it is very advisable to add computer control such as RM, when you can operate as many locos as you can see and handle in the right hand columns showing whatever locos you are interested in running, or even all of

 

your locos. The column(s) have a slide bar and up to 6 functions per loco. I can see a maximum of 6 locos on my screen, but this has been discussed elsewhere, and the maximum number depends upon factors such as screen resolution and magnification. The maximum

 

is apparently 10 with 5 per column on a top spec screen, but that is surely enough, although you can also scroll up or down the loco list very easily to find more locos.

The Elite can operate 2 locos at the same time, or even more in the sense that you

 

can set one loco off on a circuit, select another loco on even the same control knob and start that off as well. Switching between locos on the Elite is nowhere near as easy as with RM, admittedly, so you do score a few DC points in that respect.

[walkingthedog]

Fishmanoz said:

Then I don't understand how conventional single controller DCC doesn't give you positive control of 2 parts of the layout. A single controller gives you positive control of the whole layout. But maybe I'm not understanding

positive control?

When I say positive control I mean being able to speed up, slow down, stop, start just by turning a knob. If with DCC you have two locos on two circuits one would be left to chug round the other would be under positive control.

If you want to slow the on chugging round you would have to select it then the other one would no longer be under positive control.

My friend would like to control one on the main line stopping it at the station etc. but at the same time have a loco

shunting in the yard, both under positive control so using two DCC controllers. He would then like to stop the one in the yard and bring the loco on the main line into the yard without having to deselect one and select the other.

With DC you would

isolate the yard loco then pass the other from one controller to the other.

[Graskie]

With RM you wouldn't need to even do any controller handover, though, WTD. And we all know the other many disadvantages of DC operation, don't we? I couldn't possibly control 2 different locos at exactly the same moment in time on any system, anyway, and

 

wouldn't have thought anyone else could, not bang-on simultaneously.

[Fishmanoz]

To be able to have two hands on controller throttles at the same time, then turn them at the same time, you would have to do it like DC with 2 DCC controllers and fully isolated sections and an intermediate isolated section with both controllers on DPDT

 

switch.

 

But starting with one Elite DCC controller, you can set up your 2 locos on the 2 throttles and go from one to the other just by pressing the throttle to make it active. Surely as good as both at once with 2 hands?

 

But with Elite alone,

 

if you want to go to a third loco, you have to call it up on one of the throttles, and that means releasing the one that was there previously. You can overcome this with a Select walkabout, in fact a number of Select walkabouts such that you have positive

 

control of as many locos as you have control knobs, if that is how you want to do it. But this is obviously expensive and you have to live with Select limitations on all the locos you run with them. So I would never do this.

 

With RM, it is possible

 

to have 10 locos on screen at once, and just a click on their loco controller to make adjustments. Only one at exactly the same time but almost no time between them.

 

I suggested the booster solution to avoid 2 separate controllers and because you have

 

automatic control running between power districts. But just like DC, you only have anything like positive control for as many locos as you have throttle knobs or locos on screen.

[RDS]

@walkingthedog

I have done what you describe using my Elite and the Hornby Select as the other controller.

As Fishmanoz has stated there are limitations with the Select but I have not experienced those with the loco numbering system, I have adopted.

[walkingthedog]

Fishy with DC you can safely pass from one controller to the other just by crossings one pair of insulated fishplates. It doesn't matter if the front wheels are on one controller and the back ones on another as long as both controllers are sending the

 

loco in the same direction.

This is what my friend would like to do with DCC. I got the impression that it might cause problems.

 

Graskie I know RM might be the answer but I'm not sure he could cope with that.

 

As for not being able to control

 

more than one loco at exactly the same time with any system,

you must be joking. It's happening all the time. Two is really easy, three makes you think and four is a bit more of a challenge.

[Fishmanoz]

No, you certainly can't do that with DCC WTD. You'll need a section longer then longest train with IRJs at either end, then break before make switching to switch manually from one controller to the other in the section. It's not seen as a DCC issue though

 

as no one runs 2 controllers. The exception is those who have decided to run locos and accessories on separate power buses with 2 controllers.

 

Starting out DCC and not going RM, the first Hornby limit is 2 Elite throttle knobs so only 2 under control

 

at once, then add Select Walkabouts if you wish. I think at least some other brands allow for more throttles but you would have to research that.

[Fishmanoz]

Just quickly - why can't you? The DCC signal is a pulse width modulated square wave at over 10kHz. If 2 such signals go to the track, they must be phase locked with each other to not cause a short. The only way to achieve this is if they are generated

 

from the same source or controller. So even via an RLM or booster, their signals still originate from the one controller and so are phase locked. If the polarity is reversed via a reversing loop, or more correctly is 180 degrees out of phase, the module or

 

booster senses this and changes the phase to again match.

[RDS]

@Fishmanoz

First of all, congratulations on your 4,000th post.

When I used my select as a walkabout, I regularly switched from Select to Elite and back again, no problem. No IRJ's - just did it.

Now, I regularly switch from RM to my Elite and

 

back again. Maybe I have misunderstood but I do not understand why it is seen as difficult.

 

[Fishmanoz]

Oh, and the DCC signal is always present, even with nothing running. So you can't just stop all locos and switch controllers unless you have the isolating system I described.

[RDS]

@Fishmanoz

Having just seen your 4001st post.

My Elite is the common controller, everything else goes through that, RM or Select.

[Fishmanoz]

Clearly I need a life!

[Graskie]

So do I nowadays.

[poliss]

I'll try to explain how DCC works as simply as I can without getting technicackle.

Think of Morse Code. The pulses of electricity are either short or long. By varying the length of the pulses you can send words. DCC works in a similar type of way.

The

 

pulses from the controller tell the loco what to do. Every decoder in a loco has it's own address. It won't do anything until the controller sends pulses that match it's address. Then it listens for follow up instructions, which tell it what speed to go etc.

The

 

controller is sending these pulsed messages, one after another, to each decoder fitted loco.

Lets say you are using an Elite. When you add a slave controller, such as a Select Walkabout, it must be routed through the Elite in order that the pulsed messages

 

are still sent in the correct order with no overlap.

If you had an Elite and a Select connected to the track separately, then the electrical pulses would overlap and the decoder would be getting full power all the time and the loco would run away out of

 

control.

 

If you have an Elite with the 4 amp power supply you can run up to 10 locos. If you're running more than 10 locos you will need a booster, or repeater as I prefer to call them. The booster must be connected to an electrically isolated section

 

of track. If not things will go wrong. (It would be like connecting two DC controllers to the same section of track.) The booster is connected to the Elite and repeats the pulses from the Elite. The pulses are still synchronised.

 

You can have as many

 

slave Select Walkabouts connected through the Elite as allowed. I think it was eight the last time I looked. You probably won't be able to control more than two locos, comfortably, at a time, unless you're a very quick thinker.

 

[walkingthedog]

Many thanks one and all. How on earth am I going to explain any of this to my friend. He looked confused when I suggested more than one power feed to a circuit.

[poliss]

No need to explain. All he needs to know is only one controller can be connected to the track. All other slave controllers have to be plugged into the first controller.

[walkingthedog]

When he asked me the best way to lay track I said lay it flat and get the first circuit down and test it, add more, testing as you go. When your happy add ballast etc. So what does he do? Lays 2 feet of track, paints it, ballasts it, lays the next bit,

 

does the same. Lays about 8 ft of track the same way. Then he puts a loco on the track, off it goes, falls off because the joins aren't straight. Has to relay track. Unfortunately it's all ballasted and glued firmly down. Manages to lift the track destroying

 

it completely. Had to start again.

 

I rest my case my your honour.

 

This could take some time but I'll persevere.

[poliss]

Ah. In that case I suggest the Tri-ang R.854.

[RDS]

walkingthedog said:
... So what does he do? ... Had to start again...

WTD, you must keep us informed on this fascinating story.
I look forward to the next instalment!

[Fishmanoz]

Also, if he is at that level, tell him directly and firmly he doesn't need more then one controller. It is one of the advantages of DCC. He will have two trains available immediately on the two knobs on the Elite, and he can quickly and simply change to

 

a third, and a fourth, and a fifth etc. the ones he is not controlling directly will continue to do what he last asked them to do until he goes back and changes them. If he gets in trouble, there is a big red stop button to avoid disasters and give him time

 

to think before he starts again.

[walkingthedog]

I think I've worn him down enough to go DCC. Just depends what make. What he's done looks really good, just very or should I say over complicated.

[walkingthedog]

Latest news. He's got a couple of lift out sections so he can reach the far corners of the layout. One section has some siding crossing it. I said lay the track then we'll cut it where it crosses the join. He did just that. Unfortunately one of the pieces

 

of track is a set of points.

[Graskie]

That ended up as a pointless mistake then.

[Fishmanoz]

Serenity prayer WTD, serenity prayer.

[walkingthedog]

Large glass of wine fishy, large glass of wine.