Efficient calculation of CBUS power requirements

Discussion in 'General Discussion' started by brj, Jun 20, 2006.

  1. brj

    brj

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    Folks wondering if I could get some thoughts on the most efficient (read quickest but accurate) way to calculate CBUS power requirements for a given configuration?

    I've heard some people using their own excel spreadsheets (saying that this is a quick way to do rule of thumb power requirements), others using CIS tools - what is the consensus out there?

    I've also seen some other threads mentioning that there are general advantages (the specifics escape me now) in using CBUS relay modules as power supplies over the power enabled Dimmer modules and that this is more cost effective than just using dedicated power CBUS modules.

    Would appreciate any comments - many thanks!
     
    brj, Jun 20, 2006
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  2. brj

    JohnC

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    Excel for me, although I have left all my tools with my previous employer.

    It's very easy to write one in Excel, and you have to use something to record, plan and document your loads anyway.

    Once you've got a list of all the devices, it's easy to calculate the load... (even manually). What I used was a "Unit Draw" cell for each item, then filled in the mA for each device

    QtyDevices * UnitDraw = total for line, then total it down the page.

    I did another one which used text for UnitType (eg: switch, dimmer, etc) then filled in the mA automatically used a formula like this
    Code:
    =IF(C:12="switch",20,IF(C:12="dimmer",50,0))
    That is not exact excel above, just the kind of thing that I used. Note you also need error handling for blank cells, etc.

    John
     
    JohnC, Jun 21, 2006
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  3. brj

    Dave Byron

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    John
    Watch toolkit still got bug in Cat Number - thinks every unit has a power suppy.


    dave
     
    Dave Byron, Jun 21, 2006
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  4. brj

    JohnC

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    Thanks Dave, but it was irrelevant what Toolkit says... This was a stand-alone XLS file, which I used for planning purposes.

    Once I had everything worked out (ie: how many switches, dimmers, power supplies, etc - then I ordered the stuff from CIS and when it was delivered only then did I enter each item into Toolkit.

    There's only 3 ways to do the power calculation :
    a) guess
    b) work it out manually on paper
    c) work it out manually in electronic format (eg: word, excel)

    The advantage of doing it electronically is that you can then produce all your hand-over documentation... and by doing it in Excel you can apply formulas etc to automate it somewhat.

    In my case, I used the XLS to produce the quotation too... no way I was gunna enter stuff into Toolkit on the*off-chance* that we'd get an order !

    John
     
    Last edited by a moderator: Jun 26, 2006
    JohnC, Jun 26, 2006
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