[ChrisE]

Let me tell you that as someone looking to start in DCC I thought that I had the bus issues sorted before I read this thread but now I am mightily confused.

I understand exactly what a bus is & I accept that you can have as many buses as you like each of which connects to its own outlets - be they track power, signals or whatever else BUT I am now totally confused about how many wires I need to thread around my new layout.

1. I hope we would all agree that I need a track power bus and that this is 2 wires of different colours to aid identity that are connected regularly to the track so that one rail is always connected to one wire & the other colour wire to the other rail. Basically the connections from this bus to the rail should ideally be such that there is a connection to each rail between every rail joiner - eg onto every piece of track. I have learnt that the bus should not be a ring circuit but needs to terminate. I guess that in a tailchase layout for that to mean anything the track must not be a ring circuit either and must thus have insulated joiners that correspond with the break in the power bus.

2. Now it gets complicated. Some of you are telling me that I can take power for accessories from the track & some of you say not & thus that I nees a separate bus. I am totally at a loss to know whether the control signal for these accessories comes down the track bus or down the accessory bus or whether I really need one. 2 more wires.

3. I now come to the feedback bus the necessity for which seems to depend on the brand of DCC that I buy. Lenz & its cronies need such a bus whilst Digitrax does not. As I haven't decided which system to buy yet & I may change my mind that is 2 more wires. I assume that this bus needs connecting to something but I am nor sure what. If guess it is just accessories rather than the track & I am sure that I will need to make it easily accessible for that extra accessory I will buy that they haven't even invented yet.

4. As I might like to do something else on my layout like put lighting into buildings I need a separate power supply for that as well. 12v & 2 more wires & again easy access to put extras onto it in the future.

The way I count this I need to run 4 buses and thus have 8 wires. There may be others that I haven't thought of yet. When I started this I would never have imagined that I would need more colours that my electrical wholesaler can supply but it appears that I do.

How am I doing?

Chris

 

[ChrisE]

QUOTE (LisaP4)Actually by your reckoning you need 5 BUSes, you missed out the Com BUS which the throttles plug into. However DCC only requires 2 BUSes;
The Track BUS
The Com BUS
<{POST_SNAPBACK}>

That is what I thought in the first place! Yes I did forget the COM bus as I have always intended to use wireless control but I am sure that I should install the BUS anyway. I am also pleased to note that a ring circuit is acceptable.

2 things come to mind.

1. The 5 amp supply - and many have less - that sounded so generous when I started all this is suddenly sounding very small if train lighting, building lighting & accessories are all to be powered from it and

2. As a result of this I am inclined to think a 12v BUS for non DCC based lighting etc might well be a good idea. I would also think that the less "junk" I have on my track BUS the less likely I am to compromise my proper control and power supply of trains & points etc.

I remember reading somewhere that as a matter of safety discipline it is a good idea to avoid mains cable colours when wiring a layout. As in the UK that would now include at least red, brown, blue, black, yellow, green and green/yellow stripes I am not kidding when I say my wholesaler doesn't have enough colours.

Chris

 

[ChrisE]

Doug,

I do know exactly what they mean but when I look at your diagram the "two wire" for DCC does seem to be marketing fluff & frankly would be better forgotten. Beyond the Bachmann market I suspect that it confuses more than it helps.

Actually my DCC layout will have more wiring than my non DCC layout partly at least because electrically it will do more - but isn't that why we go DCC?

Chris

 

[ChrisE]

QUOTE (Doug @ 19 Jan 2006, 15:57)The Lenz feedback is slightly more complex than this, and also depends if you use occupancy detectors. With the Lenz Occupancy Detectors (LB101 ) and Feedback Modules (LR101). Each LR101 supports 4 LB101s which in turn support 2 track circuits, so for every one feedback module, you can monitor 8 track circuits or zones.
<{POST_SNAPBACK}>

I feel confusion coming on again. I really do not understand the above quote at all. I am probably the only idiot who does not understand this but does it have any implications for how I electrically construct my railway or can it wait until/if I decide that I want occupancy detectors etc?

I don't think that we have discussed track circuits & zones at all.

 

[ChrisE]

QUOTE (the volebender general @ 19 Jan 2006, 16:28)ChrisE,

They all, however, work on the isolated block system and you will find, for example, Peco code 75 track isolated at all exits provides a natural frame-work.

TVBG
<{POST_SNAPBACK}>

I now understand why you said in a post elsewhere to isolate all 6 rails in a turnout. At the time that I read it I couldn't see the reason when the outside two rails are continuous lengths. I thought that isolating the two that connect to the frog would be sufficient.

 

[ChrisE]

Moving the topic slightly. If I decide that the power supply I initially buy is not big enough I understand that I can use a booster. The question is does the booster work on the same track circuit/ bus as the original or must I sectionalise my layout so that each booster has an appropriate proportion of the track and accessories.

The diagrams suggest separate power districts & buses.

Effectively do two powers supplies of 5 amps give you a 10 amp power supply or is it two separate 5 amp supplies. which meet only as a loco crosses a necessary section gap

Chris

 

[ChrisE]

QUOTE (Doug @ 20 Jan 2006, 15:07)The idea is that you can have say your mainline powered by one power suply and perhaps the goods yard powered by a booster. Then if a loco derails in the yard whilst shunting and causes a short, it doesn't affect the mainline opperations.
<{POST_SNAPBACK}>

Thanks Doug. Now all I have to do is to work out how to model all those passengers hanging out of the windows ( I model the 60 & 70's) to view the scene of the accident!

Chris

 

[ChrisE]

Another sub topic question.

The wiring of my layout is going to be much more complicated than I would have guessed and there are going to be many many connections. If there are faults it could be very time consuming & difficult to find them.

I am planning to be able to break the BUS (what is the plural of BUS BUSes or BUSi?) in a number of places to aid the location of faults.

Am I being over cautious or ought I to do more. If more what?

Chris

 

[ChrisE]

QUOTE (Dynamite26 @ 21 Jan 2006, 00:32)I think i might just stick with DC control less confusing for me and that i have designed my layout so i can run 4 to 5 locos on DC anyway as i have 5 controllers.

I just find DCC so confusing.
<{POST_SNAPBACK}>

Dymamite26,

As you can tell I am no expert on DCC, in fact like you I am a beginner & I must admit there is a lot that you can learn BUT

When I started in old fashioned analogue it was with a simple controller and a circle of track connected by two wires. It worked OK except that I always had badly running locos and somehow I always wanted to run two locos at the same time or I was surprised when the loco in the siding that I hadn't noticed ran into something that it shouldn't have. As a result I ended up with soldering track sections together - making a BUS - and putting in sections each with a switch. Even with these sections it never felt right. I have never wanted to have more than two trains running at once because my brain simply will not cope with that.
With DCC I can get over all this mess by just having two wires from my DCC controller connected to the track in a number of different places - the BUS again.

After a few years the idea of electric points and signals became appealing. This introduced horrible amounts of cabling and the real problem that the signal & point switches were never quite where I needed them to be when I was actually controlling anything - I like to wander round my layout & indeed needed to for uncoupling etc. DCC lets me control all this from the one handset with an extra controlbox and one more pair of wires around the circuit - the 2nd BUS. No layout I have ever built has told me where locos are or which way points are set & I don't think I would know how to wire it all if I wanted it to do so. DCC can do it but you don't have to any more than you did with analogue. If you want to do so however at least I can see how to do it with DCC. I have always wanted sound on my system but it has never been possible. With DCC it is and very easily. At the moment it is too expensive for all my locos but like everything electrical it will be affordable soon.

My layout has lighting for some buildings and that comes from a separate pair of wires. No need to change that for DCC if I don't want too.

I could go on but I won't (sighs of relief all round) DCC is new and it can be complicated but I really don't think that it is as complicated as what we did before and it allows us to do all sorts of things that we could never do. My intention is to start simple - a good excuse for saving up time - like I did with analogue but make sure that I am prepared for what follows in terms of wiring. That way I won't be trying to put wires into impossible places later. I have done that too many times with analogue.

A lot of what is posted here is about the extreme end of DCC. The basics are very simple & I am sure worth it. Take comfort from the fact that Bachmann & Hornby are selling/ going to sell thousands to ordinary people and believe that they will cope. In 5 years I strongly suspect we will all look back on analogue and realise how horribly complicated and messy it really was.

If you really have uncertainties you could always start with a simple shunting plank to get the feel of it before you commit to setting up your main layout. This would always be a useful test track & could well help you avoid mistakes on a bigger scale. Didn't we all start with the simple track rather than the complicated things that we progressed to?

I am sorry if this is off thread but it did need to be said.

Chris

 

[ChrisE]

By wire block I assume you mean what are commonly known as chocolate block connectors. A row of approx 10-20 connectors that look loosely like a block of chocolate & you cut off as many connectors as you want.

As long as the connector is rated for at least the power you are going to put through the circuit you will be OK. Thus a 10 amp connector should be fine with a 5 or 8 amp supply.

Chris

 

[ChrisE]

QUOTE (Doug @ 21 Jan 2006, 01:28)On the subject of testing: When I'm constructing the track and installing the DCC signal and power BUS, Obviously I don't connect the power whilst I'm doing it, but I use a 9 volt battery - connected to a buzzer and a track power feed clip. I plug it in and if I get a wire crossed, the buzzer will go off as the track short-circuits.
<{POST_SNAPBACK}>

Sounds like a good idea. I know the way that you mean it is quite safe but can I just stress for the less electrically literate readers that this must be a dry battery - the sort you throw away when they run flat, Ever Ready, Panasonic, Duracell etc. If you use nicads, NiMh LiPolys or lead acid types the results could be burnt out wiring, fire or explosive - literally!!!!

Chris

 

[ChrisE]

I have always either soldered my rail joints or put a dropper for every length of track on a non DCC layout.

I have also never used chocolate block connecters preferring to have one long length of wire & just strip the covering and then wrap & solder the drop to it. If I am looking at a number of connections close together I have used a tag strip.

As electrical problems nearly always begin at joints and appear insidiously over time this has always seemed the best way & is no extra work as long as you fix the wires to prevent shorts.

This method is why I asked about deliberately putting in breaks with DCC to help find faults. If I used blocks with all my sidings & points I could have an awful lot of chocolate blocks, breaks in the BUS & potential problems in my wiring. I would also have a lot of breaks in the track plan that Doug published.

Am I alone in my methods?

Chris

 

[ChrisE]

QUOTE (Dynamite26 @ 22 Jan 2006, 00:36)I couldn't connect the bus to each section of track as nearlly all my track is hornby setrack and would take forever to do it,plus i'm still thinking of sticking with DC as that seem far easier to me as i just connect two wire from each of the 5 controller to each loop and to my depot area and away i go controlling my trains.
And what wire i bought can be used to wire extra lighting in the loft.
<{POST_SNAPBACK}>

My way of doing it arose because of problems with non DCC - exactly what you are proposing as the easier solution. Track joints are a major weak spot & set track has lots of them. Even if they work well when new they degrade over time & running gets worse. Relco sold lots of units to pre DCC users - one per controller - to counter just this problem. If I were going to do what you suggest I would smear very sparingly Copperslip between all my rail joints as I assembled them. You could do this just as well for DCC as it makes no difference to a bad electrical contact which method of control you use.

Chris

 

[ChrisE]

QUOTE (Branchliner @ 22 Jan 2006, 00:22)Just a couple of queries,

1. somewhere in this subject a statement was made to the effect NOT to return the bus ends e.g, like a household ring main. Can anyone give me a rationale for this. Years ago when I worked with specialized equipment we had to take care when earthing to ensure that a loop was not formed, this was to minimise the possibility of induced current. I cannot see the same problem with a ring AC power circuit.

2. It was also recommended NOT to solder droppers to the track connectors due to the possibility of poor contact with the track. If this is the case it would be necessary to connect the bus to each section of track to avoid the same bad connections, I am aware that some modellers do this but I consider it overkill.

Brian
<{POST_SNAPBACK}>

1. Neither can I & others here have confirmed it.

2. I can well understand why you should not solder droppers to track connectors. The conductivity of the joint between the connector & the track is one of the major electrical weaknesses of model railways. If you solder to the connector it is distinctly possible that over time you could have a poor contact with the track both sides of the connector. Connectors are often not made of the same metal as the rail which of course makes the corrosion problem worse. As I posted above this is one of the problems that the Relco unit helped to minimise for non DCC. I guess it all depends how sure you want to be that you will not have poor conductivity in the future.

Chris

 

[ChrisE]

Horseshoe v Ring Main BUS

There are definitely differences of opinion here. TVBG advocates a horseshoe (posts 2 & 74). Doug goes horseshoe + resistance (post 73). Lisa goes ring (post 19). There may well be others.

In a situation like this we all recommend what we have found works for us. In a newly developing sphere of expertise such as this many of us will not have tried all the alternatives. Can I thus ask this question the other way around.

1. Has anybody tried either a horseshoe or ring main BUS and found that it gave problems causing them to change? Did the change alone solve the problem?

2. Has anybody found problems with accessory or feedback BUS as above?

3. Which equipment manufacturers recommend which method?

If either horseshoe or ring has caused problems please be specific about the problem, the length of the main circuit, and the age & make/ model of the control system.

It has been suggested that with the current equipment there should be no problem with problems being confined to previous generation controllers only.

Chris

 

[ChrisE]

QUOTE (dwb @ 22 Jan 2006, 14:31)To ring or not to ring that is the question:-

Summary:
The primary DCC power supply / loco signalling path can be a ring.
All the other stuff most likely should not be.

I hope this helps. I could go into the bath water wave analogy but I take showers myself.

David
<{POST_SNAPBACK}>

Ah yes - I had been wondering about the speed of light amongst other issues. What you say suits me well. I can continue the power BUS accross my obligatory doorway crossing bridge and use it as the natural break for everything else.

Nobody has volunteered that their choice of BUS gave them a problem. Any takers?

Chris

 

[ChrisE]

QUOTE (Makemineadouble @ 22 Jan 2006, 19:17)My only comment is that using a telephone in the railway room was impossible with the layout powered up. There was zero interferance outside the room, and zero interferance with the TV's.

<{POST_SNAPBACK}>

Interesting comment as Lenz use a wireless telephone handset & base station as their remote.

Chris

 

[ChrisE]

I assume you are jesting about the TV but I really still don't see the problem here. Your house is full of wires carrying 240v ac which will do much more than the 16v ac that a model railway BUS runs at.

Any piece of electrical equipment sold in the UK, as I understand it, has to be CE compliant & one of the tests this includes is introducing radio interference. That covers your DCC boxes.

On this basis I cannot see that a model railway should interfere with telephones any more than the mains cables in the wall of your model room & I would be very surprised if it caused interference with anybody's TV unless you have a very marginal signal.

It would be a major failing if DCC could not be used near telephones or TV aerials!

Chris

 

[ChrisE]

Please please please please lets not start discussing the capacitor/ no capacitor issue!!!!!

Chris