Help wanted

Discussion in 'General Discussion' started by welshman, Apr 17, 2011.

  1. welshman


    Apr 17, 2011
    Likes Received:
    Melboure, au
    Just wandered if anyone can help me? I'm totally new to cbus and in the process of trying to install a new system to control the lighting in a new cafe/bar in St Kilda, Melbourne. It's probably the most basic of systems but I'm having trouble getting a straight answer out of anyone.

    The system is wired thus...

    1. Cbus cat5 from the LCD control panel back to the cbus board.
    2. Some 20 channels worth of switching from the board (these include a requirement for LED strip dimming, fluro light dimming, straight on/off fluro switching and dimming of down lights and track lights).

    So my questions are...

    1. Do i need a PC interface?
    2. Can a dimming relay do straight on/off switching for my fluros?
    3. Does 1A per channel have any tolerance? i.e will it cope with 1.3A or at least 1.08A?
    4. Is it cheaper/easier to buy modules with in built power supplies or do I buy the power supply module?
    5. Do i need the Dali gateway for the dimmable fluros? If so can I also use it for dimming the LED strip lights? What is the output voltage of the Dali module?
    6. With the cbus board being directly adjacent to the main switchboard what is the preferred method of 240v supply? Individual rcbo's in the switchboard direct to the modules? Or one supply in to the cbus board and then rcbo's?
    7. With electronic transformers, LED drivers and dimmers, and lights with integral transformers do I need a universal dimmer of will a standard dimmer module work?

    I know this is a lot of information to ask for and I'm sorry for that but if anyone could help in some way it would be greatly appreciated. Or failing that if anyone knows of someone in Melbourne who might be able to meet up with me or speak to me over the phone then that too would be appreciated.

    Many thanks
    welshman, Apr 17, 2011
  2. welshman


    Nov 11, 2009
    Likes Received:
    Some pointers

    1. A PC Interface, or a CNI is needed to program the system. You also need a computer and the toolkit programming software.
    2. I think the newer ones can do this
    3. I would stick with staying within the recomended tolerances
    4. Easier to buy units with built in power supply, less space and less wiring. You need to calculate how much power supply is required, too little or too much is a problem.
    5. DALI gateway used if you have specified DALI dimmable lights. You also then need to think of programming for the DALI system, as well as the CBus system. The DALI system works by containing programming within the lights DALI ballast. The CBus DALI gateway acts as a kind of translator, converting CBus control signals into DALI control signals
    6. Flexible, check with your local electrical regulations. Wiring for controls is kept seperate from wiring for output circuits. So on a relay, a breaker for one or more channels may trip, but the units control power supply stays on as it comes from a seperate breaker. Meaning that other output channels still work.
    7. Different lights work with different types of dimmers. You need to check the specifications of transformer type and electrical characteristics and determine right type of dimmer. If LED drivers have dimmers and this is not a DALI system, you need to determine how CBus will control the dimming. This could be a C-Bus analogue output unit interfaced to the LED dimmer control unit.

    You don't say what type of LCD display screen you are using, is this is one of the touch-screen units you also need to use the PICED programming tool to program the unit.

    It sounds like you do need a C-Bus programmer. Even on relatively simple jobs you are still dealing with a technology where mistakes or oversite through inexperience can prove expensive. You would also find the experienced programmer would be able to get more out of the system. I would imagine there would be somebody local to you.

    Good luck
    SBL, Apr 17, 2011
  3. welshman


    Aug 3, 2004
    Likes Received:
    Adelaide, South Australia
    Welcome to C-Bus! Once you're over the initial learning curve you'll find there's thousands of things you can do with it.

    C-Bus Toolkit is the software application you use to program all the devices in your system. It needs a connection to the C-Bus network to be able to program the devices. There is a push-button configuration mode called Learn Mode that enables basic things to be configured without using Toolkit, but it's naturally limited and the need to program an "LCD control panel" will mean you'll need to have the network configuration in Toolkit prior to commissioning the panel using PICED anyway.

    You can use the "LCD Control Panel" as the PC interface to the C-Bus system, assuming it's a B&W or Colour Touchscreen you're referring to when you say "LCD Control Panel", however whilst you're using it in this mode it ceases to function as a touchscreen. You're probably better off buying a Serial, USB or Ethernet C-Bus Interface which will give you the flexibility to put the interface somewhere comfortable, rather than having to balance the laptop on your knees whilst programming the C-Bus network through the touchscreen.
    Dimmers and Relays are two different types of units; there's no such thing as "dimming relays". I assume what you're referring to here is a C-Bus dimmer. You should never connect a dimmer to a fluorescent load, unless it specifically has a phase control dimmable ballast and these are quite uncommon. Whilst the fluoro will turn on and run at full brightness, when the channel is off there is a small amount of bleed current present and this may be enough for the fluoro to try and start. This will shorten the life of the fluoro significantly and the flickering will be unacceptable to your client.

    If you're referring to the standard DIN relay units, they can handle 10A of fluorescent load.
    Overloading the channel will run a real risk of activating the over-temperature protection circuitry in the dimmers. You'll also void your warranty. Clipsal may refuse to offer technical support if they find out you're running any of the products outside their nominal ratings. If the 1A rating of dimmer channels is an issue for you, there are 2A and 2.5A DIN mounting dimmer units available, and higher power dimmers that go all the way up to 20A per channel.
    It's cheaper and easier to install the units with in-built supplies. You use less DIN space and there's less units to wire up. You do need to calculate your power needs prior to ordering your units though, and that means using the in-built calculator in C-Bus Toolkit. On the down side, if you ever need to just isolate a section of your fixed wiring and need to turn a dimmer or relay off, you're also turning off a network power supply and, depending upon how much extra capacity there is in the network, may make the network stop operating. You also need to keep the total power supply to the network at or under 2A.

    One distinct benefit of separate power supplies is that you don't need to think when ordering your dimmers and relays... you just buy them without power supplies and then add stand-alone power supplies to the system until you're done. It's also easier to replace just a power supply if it fails rather than a whole dimmer/relay. Stand-alone power supplies can also be sprinkled around the installation to minimise voltage drops on long cable runs.
    DALI is another world when it comes to control systems. It has it's own protocol, quirks and installation requirements. If it's just a couple of fittings and DALI something you're unlikely to use again soon, I'd be inclined to stick with 0-10V, DSI or DMX control of your dimmable fluoros and LEDs as these systems have practically no commissioning requirements. Commissioning DALI can be quite a pain but it is becoming fairly common for fluorescent fittings. There are also plenty of LEDs out there that can work with conventional phase control dimmers. If you can't get phase control dimmable LEDs then I'd get DMX controllable ones and use a DMX gateway.

    The C-Bus DALI Gateway doesn't have an output voltage as such. DALI is up to about 22.5V and the devices communicate with each other by briefly clamping this voltage down to less than a few volts. On each DALI network there can be 1, and only 1, 250mA power supply and this is a separate unit to the C-Bus DALI Gateway. DALI is not an SELV system so it's wiring requirements are very different to C-Bus.
    As SBL says, this is flexible and there's no best answer. The perfect solution is also the most expensive so, like many things, there are trade-offs. Once you've considered the legal requirements, think through the various isolation levels you'll need and the various faults that may occur. Work that back through to determine which breakers or RCD's will trip under what circumstances and what impact that will have on the system as a whole.
    There's no "one-size-fits-all" to this sort of thing, although the C-Bus DIN Universal dimmer isn't a bad choice here. It auto-detects Leading or Trailing Edge dimming modes based on the type of load. You really need to either properly understand the dimming requirements of the fittings the client has chosen or, if you have a say, buy fittings and dimmers that will work together.

    For "electronic transformers" I'll assume you're talking about halogen down lights. The transformer needs to be designed to be dimmable so don't assume that they can all be dimmed. Ideally a Trailing Edge dimmer should be used with these (C-Bus Universal dimmer) however some will work with Leading Edge dimmers (C-Bus regular dimmer) but there is a limit to how many you can connect to a DIN Leading Edge dimmer as the total capacitance per channel needs to stay under 300nF.

    Some of the LED loads are designed to work with Leading Edge only dimmers, yet present themselves as a capacitive load type, making the Universal dimmer run in Trailing Edge mode, making them not dim properly. Other LED loads are designed to work with any dimmer, however you need to be mindful of the capacitance limit of the Leading Edge dimmers. Speaking generally, you should always try to use a Trailing Edge dimmer (C-Bus Universal dimmer) with an electronic-type load.

    Lights with integrated transformers will most likely have electronic transformers inside.

    To reiterate, you really need to check the dimming compatibility of the loads you're installing. It may be the case that a few extra $$$ on the load might more than make up for itself by only needing a Leading Edge dimmer, and not a Universal.

    As SBL says, you haven't specified which "LCD control panel" you have, but if it's one of the touchscreen ones you'll need to program and commission it using the PICED software, not Toolkit. I'd also highly recommend a C-Bus basic training course. It's well worth the money because you get approximately the value of the course back in equipment they give you and you'll learn all kinds of hints and tips that will save you both time and money.
    Last edited by a moderator: Apr 17, 2011
    Newman, Apr 17, 2011
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