DCC Bus

12777 Views 33 Replies 15 Participants Last post by TonyDaly, Jun 17, 2008

Brian

Discussion Starter · Feb 13, 2008

Hi all
I have been reading with interest on another forum the topic of whether of not the power bus (which also carries the DCC data signals) should/can be wired under the layout as a ring or radial circuit. Searching the internet I can't find any reference to ring circuits being used anywhere, as they all refer to radial power buses.

Will any short circuit currents be better and fast returning via a ring or a radial bus
Will the data on the power bus be best served by a radial or ring circuit?

So, is a DCC ring bus advisable or is it to be the radial or perhaps it just doesn't matter?

21 - 34 of 34 Posts

Sol

· #21 · Feb 19, 2008

Poliss, if new DCC modellers have trouble understanding 'bus' & "radial', etc, then they would be better off purchasing a basic book on DCC such as the one by Ian Morton - Aspects of Modelling - Digital Command Control.
It is aimed at the newcomer to the hobby & I even purchased one last month when I converted to DCC even though I have been exposed to it for about 2 years.

TonyDaly

· #22 · Feb 19, 2008

QUOTE (Sol @ 19 Feb 2008, 08:47) <{POST_SNAPBACK}>Poliss, if new DCC modellers have trouble understanding 'bus' & "radial', etc, then they would be better off purchasing a basic book on DCC such as the one by Ian Morton - Aspects of Modelling - Digital Command Control.
It is aimed at the newcomer to the hobby & I even purchased one last month when I converted to DCC even though I have been exposed to it for about 2 years.

An excellent book. I have a copy myself & found it very helpful. Great reading for a newcomer.
Regards.
Tony Daly.

Gordon H

· #23 · Feb 19, 2008

QUOTE (poliss @ 19 Feb 2008, 01:28) <{POST_SNAPBACK}>The language needs to be simplified. To most people, a bus is something you catch, radials are the tyres on the bus. Choc boxes are what you give your girlfriend on Valentines day. Daisy chains are things girls make at school.
The problem here is that the language has already been simplified, or at least adapted from elsewhere, to be rather more descriptive than precise.
This, of course, is part of the overall problem - so few people are familiar with technical matters, and the terminology involved, that these more descriptive versions become prevalent, often leading to their use in several different, and usually unrelated contexts. Spare a thought for those of us using a PCB design program which uses the term LMS for 'Library Management System'. No matter how hard I try, the obvious railway context simply refuses not to come to mind first!

From my point of view, I will admit that I find it hard not to want to know how things work, especially when they are related to my usual spheres of activity (i.e. electronics). I cannot imagine being in a position where blind acceptance of things magically working around me without at least a rudimentary understanding of the principles involved is acceptable.

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poliss

· #24 · Feb 19, 2008

I bet the chappie who named the Library Management System was an LMS fan who sat and thought for hours about how he could fit LMS in somewhere.

iansa

· #25 · Feb 19, 2008

[ I cannot imagine being in a position where blind acceptance of things magically working around me without at least a rudimentary understanding of the principles involved is acceptable.
[/quote]

The old saying says " I don't know how the watch works but I can tell the time".

30yrs in model railways, the last 13 in DCC and the old saying has served me well.
Happy DCCing
Ian sa

Gordon H

· #26 · Feb 20, 2008

QUOTE (iansa @ 19 Feb 2008, 23:31) <{POST_SNAPBACK}>The old saying says " I don't know how the watch works but I can tell the time".

30yrs in model railways, the last 13 in DCC and the old saying has served me well.
Then I guess you see yourself as the Managing Director of your railway, rather than the Chief Engineer?

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iansa

· #27 · Feb 20, 2008

QUOTE (Gordon H @ 20 Feb 2008, 13:26) <{POST_SNAPBACK}>Then I guess you see yourself as the Managing Director of your railway, rather than the Chief Engineer?

She who must be obeyed is the Managing Director, I am the Chief Engineer( despite not knowing how the watch works), general roustabout and everything in between.
Happy DCCing
Ian sa

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malcolmsalmon

· #28 · Mar 18, 2008

Hi....It doesn't matter if you are too technical or not technical enough. You cannot please all of the people, all of the time. I am very new to DCC but ran my own electronics company for 28 years. I am trying to get as much info about DCC into my noddle as my ageing grey cells will allow. If a posting gets too technical, I can either ask for further explanations or just pass on to a different posting. I am never happier than when I am learning something new so keep up the technical postings PLEASE.
Malcolm.

32c

· #29 · Jun 17, 2008

QUOTE (Richard Johnson @ 18 Feb 2008, 14:02) <{POST_SNAPBACK}>Hello Doug

Use a 1 watt 150 ohm resistor in series with a 0.1mfd ceramic or "monolithic" capacitor. Neither is polarity conscious. wattage of the resistor isn't critical - anything 1 watt upwards will be fine if 1 watt not available locally. Cost of these parts will be less than 50p

wiring is bus wire 1 > resistor > capacitor > bus wire two.

No need to change values at all withing the normal 11~18volt range of DCC bus voltages.

Richard
DCCconcepts

32c

· #30 · Jun 17, 2008

Hi Richard,reference to the dcc bus radial wiring due you add stubbers to both ends or one end,thanking you Mike.

Richard Johnson

· #31 · Jun 17, 2008

QUOTE (firefly @ 17 Jun 2008, 15:04) <{POST_SNAPBACK}>Hi Richard,reference to the dcc bus radial wiring due you add stubbers to both ends or one end,thanking you Mike.

***Hi Mike
Rule of thumb is one on eac "branch" of the bust, but with a smallish to mid size layout one end is adequate.

If its bigger than the average spare room then presuming the bus is a Tee shape add one both ends.

If in doubt do it both ends / if there are three branches to the bus one on each - it can't hurt to slightly overkill their applicatiton and the parts are very cheap...

Richard

TonyDaly

· #32 · Jun 17, 2008

Hi Richard.

Can the end of your bus wires be connected directly to the track or do you need to end them in a terminal block ? If connected directly to the track,you wouldn't be able to fit stubbers or does that matter ?

Richard Johnson

· #33 · Jun 17, 2008

QUOTE (TonyDaly @ 17 Jun 2008, 17:11) <{POST_SNAPBACK}>Hi Richard.

Can the end of your bus wires be connected directly to the track or do you need to end them in a terminal block ? If connected directly to the track,you wouldn't be able to fit stubbers or does that matter ?

***Tony, by definition a bus goes under the layout and is connected to the track at many places. If it is simply one pair of wires to the track and they are short, its not a bus really - just track connections. In this case I'd connect it across the two rails at the point furthest from the two track power wires.

If yours is a true bus with droppers from the rails and you simply also connected the bus to the track at the very end, then simply add the suppression/termination across the two bus wires close to the end - the benefit will still happen.

regards

Richard
DCCconcepts

TonyDaly

· #34 · Jun 17, 2008

QUOTE (Richard Johnson @ 17 Jun 2008, 12:26) <{POST_SNAPBACK}>***Tony, by definition a bus goes under the layout and is connected to the track at many places. If it is simply one pair of wires to the track and they are short, its not a bus really - just track connections. In this case I'd connect it across the two rails at the point furthest from the two track power wires.

If yours is a true bus with droppers from the rails and you simply also connected the bus to the track at the very end, then simply add the suppression/termination across the two bus wires close to the end - the benefit will still happen.

regards

Richard
DCCconcepts

Thanks Richard. Was just wondering.

21 - 34 of 34 Posts

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