DC or DCC this is not the question.

Discussion in 'DCC Control' started by paul_l, Mar 21, 2021.

  1. paul_l

    paul_l Staff Member Administrator

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    Ok so what is he prattling about.

    I think the problem with the DC \ DCC conversation, is we keep looking at the very big picture of massive layouts with big control system, where in reality the majority of us

    Lets look at the basics, we keep hearing DCC only needs two wires, and for the simplest of layouts - an oval it does, and for the same layout so does DC.
    Why ?, well all we are doing is controling a single loco, we'll leave multiple loco's out of this for a wee while to hopefully keep the DC users onboard for a bit longer.

    So lets separate Loco control from Layout control.

    Loco Control

    Now very few DC users will still be using a simple resistance controller - ok hands up I still have an H&M Duette, and it did until recently get used for running loco's in, but for layout control most have moved to feedback (back emf) based controllers. Some of the controllers have additional features including momentum, braking etc, etc.
    Strangely enough the same features offered by DCC, the only difference between the systems is that DC has the gubbings in the controller, and DCC puts the gubbings in each loco.
    The big advantage DCC has over DC in this case is that as each loco has its own controller (decoder) so can be customised to suit the loco.
    The big disadvantage of DCC compared to DC is that every loco has to have a decoder, so is more expensive to deploy.

    So why would you want to pay the extra for a chip for each loco.
    We'll assume we have a well running loco in DC - if it don't run well in DC then it won't run well in DCC either.
    Put simply the level of control that DCC gives over the loco is amazing, as is all down to customization and close proximity of the controller to the locomotives motor and functions. Now, yes this does take time and effort and there is a learning curve, coupled with not all decoders are equal, and the old addage you get what you pay for is often very applicable.
    But if we keep it simple, even just setting the start voltage - the voltage at which the loco's motor will start to move, when you set the loco to speed step 1, the loco's motor will start to rotate - a pulse at a time. Something very difficult to do on a DC controller as each motor has a different start voltage and you have to overcome the initial mechanical resistance of the loco, often visable as loco's starting off like a scallded cat - honest no cats were injured in determining these comments.

    And now the biggie - as soon as we progress from a single loco on a simple oval, and install loops, sidings etc, etc, and want more than one loco on the track, then in DC we have to start and wire in isolated sections, cab / section / loop controls, additional controllers, the majority requiring wired back to a control panel(s). However, in DCC all tracks are live all the time, and as each loco has its own controller chip, it can move independantly from another loco on the same piece of track, operated by the same or different operators.

    Up to now I've not mentioned sound - another Marmite (or Vegamite for our southern hemisphere bretherin) moment, I think you either love or hate it, and I'm still not sure which camp I'm a member of, done subtly it can be very effective, but 8 hours at an exhibition with a Class 20 blaring away, can drive you to the point of wanting to hurt someone - just my opinion tho.
    Also directional and fixed lighting, in DCC is another simple, easy to control and very effective addition to a loco and train where as with DC is more difficult to configure / activate / deactivate, and will fade or disappear as the loco stops.

    You don't need a computer to use DCC, and a lot of the cheaper entry level systems don't have a computer interface available, ah but when you do have access, this opens up another aspect entirely, allowing easy management of your locomotives and to easily edit the fine control of the locomotive and its functions.

    Here is a simple Decoder Pro Roster

    upload_2021-3-21_12-8-42.png

    Selecting a loco entry clicking on Program will bring up the edit page for the loco

    upload_2021-3-21_12-10-22.png

    All of the above can be edited from the DCC command station / handset, by editing individual values - but is far simpler using a PC.

    The features shown will vary on the decoder, the above decoder is an ESU LokSound V3.5 sound decoder, so has speed tables whitch you can edit to suit how you want it to react

    upload_2021-3-21_12-19-23.png

    or if you want to keep it simple

    upload_2021-3-21_12-23-1.png

    just set the start mid and max speed settings, allowing you to tame that wild stallion in to a well mannered work horse.

    Lunch time I'll be back

    Paul
     
  2. Jim Freight

    Jim Freight Full Member

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    This thread should unleash a Pandora's box of worms :avatar:

    Jim
     
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  3. Walkingthedog

    Walkingthedog Full Member

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    On my OO layout I sold last year I could operate 4 locos, I had a Gaugemaster 4 track controller. One on the outside circuit, one on the inside, one in the loco shed area and another the good yard. All 4 locos were under direct control. I could stop, start, accelerate, brake and change direction of any loco instantly without having to think which loco it is. I knew which one it was by where it was and which knob to turn. Simples.

    No sound (bliss), perfect speed control.

    Now I have O gauge I operate two locos at the same time. Same thing.
     
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  4. Walkingthedog

    Walkingthedog Full Member

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    Further to the above, if I want some sound I ask Alexa play steam engine sounds. There's chuffing, squealing wheels, clanking and the occasional whistle, plus other background noises, and they sound real not tinny. :thumbs:
     
  5. Jim Freight

    Jim Freight Full Member

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    I used to use electronic speed controls on DC with good results too, but that was on a large works club layout with a 12 driver cab control system, large complex control panels and an extensive set of wiring diagrams produced my professionals. The layout was transportable to exhibitions in a 2 ton truck and being a young fit member with a technical background and skill set I spent much time underneath on maintenance.

    Never again!

    So when I had the opportunity to start building my own largish layout in 2010 DCC was relatively new (well to me anyway), it was the way to go, be thorough and the rewards are significant, otherwise you dig a deep hole of despair for yourself lined with wasted cash.

    I only use DCC for loco speed control, no sound, an added joy no track sectioning (was always in the wrong place), bliss :thumbs:

    Yes I am a strong advocate of DCC, but I am even more an advocate that one builds one's railway whichever way it pleases you, i.e. Rule 1!

    Jim :scratchchin:
     
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  6. Jim Freight

    Jim Freight Full Member

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    Wow, a use for Alexa. :hammer:
     
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  7. Walkingthedog

    Walkingthedog Full Member

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    I did consider converting to DCC on my OO layout but converting over 100 locos was far too expensive. Also remembering which ID code was with what engine was too much for my brain. Give then the same number as the loco has on its cab they said. I can’t see the bloody number I said. :avatar:
     
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  8. paul_l

    paul_l Staff Member Administrator

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    The long lunch was worth it :avatar:

    Before replying to the above, i'll finish where I started, you'll see why in a few lines time - well maybe more than a few lines :whatever:

    Layout Control

    Now I'm not talking full automation, as I don't think DC or DCC becomes an important defining issue as both have advantages and disadvantages for these sort of systems, it becomes the method of control that determines how you control your locomotive movements.

    I'm talking about point, signal and all the other things we control on our railway empires.

    And here's the rub for DC users, this is where you really need to look at DCC and the control bus types of layout control.

    When we build our layouts, very early on in the design we make decisions on how we will operate our layout,

    For points this is a binary choice, electrical or mechanical.
    Mechanical - finger operated, wire in tube, levers, bell cranks etc, etc.
    Electrical - Solenoid, slow motor, stall motor, servo, stepper motors etc, etc.

    For track sectioning - the well organised (not me :whatever:) would do this at the very start of the process, I did it half way through once the majority of the track was down, and I was about to start the wiring :hammer: and yes this is an issue for DCC as well but not as critical.

    For DC you need to decide how many loco's will be in motion at anyone time, where and how you are going to seperate them, and isolate all the others still on the layout. Then how to route the power from the desired controller to the desired section, which leads to some weired and wonderfull wiring solutions bearing more of a resemblance to a GPO switch center than a hobbist control panel.

    For DCC, you need to work out roughly how many locomotives will be on the layout at the busiest time, and estimate how much power they will consume. Remembering with DCC the track is always live, and any locomotive on the track consumes power (may be minimal but it adds up).
    For example an NCE PowerCab is rated at 1.5A, and a OO gauge Heljan Class 26 consumes 0.4A when moving 0.45A if the lights are on, so I shouldn't have more than 3 of these on the layout at anyone time, now this is a worse case, as my Bachmann Class 24 with sound, uses 0.05A stationary, 0.1A with sound on and between 0.12 and 0.25, therefore in this case I could have 6 locomotives in motion, and 15 sitting stationary but with the sound on (God forbid 15 Class 20's ticking over).
    For DCC layouts that will regularly use more than 50% of the systems power rating, I'd suggest using additional power boosters, and splitting the layout into Power Districts, loco depots often have there own power district.
    The difference between a DC section and a DCC power district, a DC section has to be connected to the correct controller to be able to operate the loco, on DCC, the loco just passes from one power district to the next, the operator isn't aware of moving from one district to the next.

    I'm also a great believer of rule 1, and have no intension of preaching the gospel of one to the other. However, here is the point for DC users, don't just think DCC has to run everything, just pick the bits you want to use.
    DCC / Control bus systems can operate the layout - that is your track etc is wired for DC and your loco's operate in the normal manner with all the sections etc that, that entails. However your control panels, layout switching, signalling, accessories etc are controlled by a DCC / Control bus based system.

    What are the advantages, wiring becomes an awful lot simpler, basically 2, 4 or 6 wires - I'll come back to that in a few lines.

    Just a quick overview of DCC,
    A DCC system has 3 distinct parts,
    Command Station - this is the brains, it controls everything, there can only be one - and we're not talking Highlander here.
    Cab or Interface Unit - normally a handset, but could be control panel, it's just a method of sending instructions / requests to the command station
    Power booster - the brawn
    These can be seperate items or any combination of the 3 joined together, for example the PowerCab, is a PowerPro Handcontroller, Command Station and 1.5A Powerbooster in the one unit. Where as the 10A PowerPro system uses seperate CS02 Command station, a PB110 10A power booster and PowerPro handsets to enter the commands.

    DCC systems control and communicate over buses,
    Three main types of buses:

    Single direction or broadcast, i.e. Commands are sent over the buses, with no confirmation required or looked for. The track bus is the main example, where the commands from the Command station are broadcast to all decoders, the decoders listen for a command for thier address and then act on the instructions. I think all the systems call it the track bus or just labelled track.

    Command Bus - Bidirectional bus that the control devices communicate between themselves and the command station, and in some cases between the devices without the need of a command station. This bus normally is propriety, and may or may not allow interoperation with other companies devices. On NCE it's called the CAB bus, Digitrax it's called Loconet, Lenz - Xpressnet, MERG CBus etc etc.

    Control Bus - Dedicated bus to send commands from the command station to the boosters very similar to the track bus but far lower current capability. Not always present on smaller units.

    Ok back on track - so to say

    If all you want to do is control points and signals, then the two wire track bus is all you would need to route around the layout, just tapping off the bus where ever an accessory decoder is required to operate a point, signal etc etc.

    If you require to enter commands or provide inputs to a system then a four wire command bus to link the input devices and if still required the 2 wire track bus as well.

    Those who love mimic panels will love the MERG CBUS system, which uses the Industry standard CanBus system for the communication protocols, which results in an almost bullet proof system, with cheap components, and has the ability to be used without a command station. Each unit can be programmed to respond to changes on each other - something I am trying to learn at the moment, seemingly once you get it its simple :headbanger:hopefully soon.

    We then come to the feather in the Cap the computer interface, if your chosen system has a computer interface, and it's supported by JMRI, then you can look at using PanelPro (Part of the JMRI suite of programs - all free and open source).
    With this you can create Mimic panels of your layout and operate the layout from a touch screen, with points, signals etc all being set from the panel. Your job is now to drive the train via your controller DC or DCC doesn't matter.

    Hopefully I've not started a flame war, but have blurred the walls between them a bit.

    Paul
     
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  9. paul_l

    paul_l Staff Member Administrator

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    IN BR - Model Scottish loco's they used bigger numbers, otherwise I suggest early LMS

    upload_2021-3-21_17-34-13.png

    :avatar:
     
  10. Jim Freight

    Jim Freight Full Member

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    Got that tee-shirt, especially as I prefer to buy weathered goods locos :hammer:

    This is where using iPods with wifi link to my Lenz system allows the use of a descriptive labels applied to the loco as well as using binoculars to train spot :avatar:

    Jim
     
  11. Jim Freight

    Jim Freight Full Member

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    Oh I think some will now be put off completely, others will stand and fight, don't how you are going to sleep tonight as the artillery digs in for an all out assault of DC Vs DCC and not forgetting AC from the era of TTR :giggle:

    Rally around your flags folks, a storm is a brewing :drums:

    Jim :)
     
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  12. Walkingthedog

    Walkingthedog Full Member

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    Thank you Paul. I friend said to me if I had DCC I could run the whole layout with a computer. Wow said I, then I could switch it on and go out for the day. No need to get involved with the layout once it is built. Stupid boy. :facepalm:
     
    Last edited: Mar 21, 2021
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  13. Sol

    Sol Full Member

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    I grew up on DC & even worked with it in telecommunications but when I rebuilt my layout that ideally required 4 people to operate it & after being exposed to DCC, I went that way. (No sound though, as Paul said, it can be distracting if ones hear that loco 12 feet away.)
    Ideal for when 4 locos with 4 different drivers are all working in & through the same station - doing that via DC would have been a real nightmare in having 4 sets of hands on the panel switching their bit of track to their controller.. also the problem of remembering loco numbers doesn't happen as all trains are driven under a Train Order which not only has directions but loco number as well.

    But each layout is unique so whatever method works for you, good
     
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  14. Walkingthedog

    Walkingthedog Full Member

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    I think DCC is just another means to an end. Something else will appear one day, some will love it other won’t. Each to their own.
     
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  15. paul_l

    paul_l Staff Member Administrator

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    Spot on Brian.

    It's always good to have a religious debate on a Sunday - almost :avatar:

    I would say tho', that my biggest argument with DCC is the different propriety standards for the control buses, and yes I can understand each company protecting its market, but effectively stops me buying non NCE equipment as they're not compatible, the danger is that someone else may produce something that makes me need to move to thier system and I'm then a lost customer. Now that is unlikely to happen (wait for it as I prod the bear in the other rib) as already having the best system why would I change :avatar:, but actually the real reasons for the lack of need to change for me are firstly I like the handset, the hammerhead just fits nicely, and secondly, any lack of features can be added via JMRI acting as middleware between my NCE systems and any other supported system.
    For example, I use JMRI to act as a middleman between my NCE, MERG and Wifi tablet devices.

    Paul
     
  16. Jim Freight

    Jim Freight Full Member

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    I shall stick with Lenz, it was the best option that fitted my requirements when I started and to change now would be an unnecessary expense for little gain. I'd only consider changing if I had to start again from scratch. :whatever:
     
  17. Keith M

    Keith M Staff Member Moderator

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    I am starting again Jim, this time with an 0 gauge layout rather than 00 gauge which I am presently intent on keeping for the time being, but I have again gone for the Lenz setup, no point in having 2 different systems and trying to learn what can/cannot be done with each system. At almost 74, I can have enough confusion in my life without looking for more, so I'll stick with what I know (or at least, can remember!).:giggle:

    Keith.
     
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  18. Jim Freight

    Jim Freight Full Member

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    If I am forced to restart, I too will migrate to a much simpler O gauge layout but retain DCC control. :)
     
  19. Walkingthedog

    Walkingthedog Full Member

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    Changing to O gauge last March, aged 70, was the best decision I have made for a long time.
     
  20. paul blythe

    paul blythe Full Member

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    I notice that hornby are going to produce an analogue system that uses your smartphone or tablet as the controller. does anyone have any thoughts on this? I believe it offers some of the benefits of DCC at a much lower price. my father has a large 4mm layout and for the sake of £30 i may get him one. he wont go dcc as he has too much stock to buy decoders for. one of the things that interests me is that you can draw your layout on it. I dont know how it knows where your loco is on the circuit but it apears you may be able programme the running of up to 8 circuits
     

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