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    Pat Immel
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Dimmer doubler noob

Hello All,

 

I will be using our dimmer doublers for the first time on our upcoming production and I have a few questions:

1.  In a perfect situation, the two fixtures to be doubled would be more or less right next to each other, but in my situation, (studio theatre with three large rectangular trusses) one unit might be in one location and the second unit might be on the opposite side of the truss. My doublers have twist lock ends on them (for obvious reasons!)  I'm just not quite sure how to handle this situation.

2.  I create my plots in Vectorworks Spotlight (v2009sp2) and then output the patch to my ION.  How do I note this on my plot to take advantage of the dimmer doubler.

3.  How does the doubled dimmers actually appear on the console?

Sorry if these questions are overly simple.  I am good with my ION and good with Spotlight, but this is kind of throwing me and I want to have it figured out before tech!

Thanks,

  • 1. You are going to need extension cords with the appropriate connectors to connect longer runs. The twist-lok is used in part as a safety feature to mitigate the chance of accidentally connecting an instrument with a 77V lamp into a 120V circuit. You DID remember to change the connectors on your instruments to twist-lok.

    2. If it were me, I would use the A/B convention on my plot, dimmer 1 doubled becomes 1A and 1B. You could use absolute addressing 1A = 1, 1B = 257 (DMX default) or 20001 (ACN default) but I find that the A/B suffix serves as a reminder that the circuit is dimmer-doubled.

    3. Ion allows you to reference the dimmer using A/B notation or absolute address. I use A/B notation. When you are done patching, the dimmer shows up with whatever channel number you've assigned, just like any other generic dimmer would.

  • Hi Pat -

    First off, you're right in thinking the doublers have twist-lok for good reason.  The best thing to do is build some jumpers; use 12/3 SO (or SJO, if the cable is staying in the grid & no one will be stepping on it), and L5-15 twist-lok connectors.  Since dimmer doubling is so popular here in NYC, most of the bigger rental houses stock a fair amount of L5-15 cable for this reason.

    I can't tell you much about how VectorWorks deals with dimmer doublers; but I think it will let you put in "Dimmer 1A", "Dimmer 1B" etc.

    This is also how the dimmers look on the console.  You will have to set the output for dimmer doublers; essentially what that does is "split" the universe in half, so dimmer 2A is still DMX 002, but dimmer 2B is actually controlled by DMX 258 (1-256 for A side, 257-512 for B side).  But it's a whole lot easier to just patch "2B".

    You'll also want to make sure you have 77-volt HPL lamps on the dimmer doublers, and you'll have to change the firing mode on the CEM from Normal to "Doubled" or "DD".

     

    Good Luck!

     

    Rob

  • in reply to Rob 4Wall

    Thanks for the info guys!!  I'll look into making jumpers.

     

    Pat

  • in reply to Pat Immel

    I am not sure why you would need 12/3 SO jumpers for 15 amp connectors with single 550w 77v lamps drawing a bit over 7 amps.  16 gauge should be plenty.

     

    Eugp

  • in reply to Rob 4Wall

    Rob 4Wall said:
    ...The best thing to do is build some jumpers; use 12/3 SO (or SJO, if the cable is staying in the grid & no one will be stepping on it), and L5-15 twist-lok connectors.  ...

    Don't use SJO, as this application does not meet any of the exceptions to Extra-Hard Usage cord as specified in NEC 520.68 and 520.69.  As for 16/3, if at all possible, I like to meet or exceed the connector's rating, thus 12/3 or 14/3 minimally.

     

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