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DMX Splitting...

Discussion in 'Lighting and Electrics' started by Flyboy, Apr 7, 2008.

  1. Flyboy

    Flyboy Member

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    Occupation:
    Master Electrician / Rigger
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    I'm familiar with DMX splitters to go from a single input to multiple outputs, but does anyone know if there exists a means to go from multiple sources to a single output? (ie. from two different boards to a single DMX line)?
     
  2. Grog12

    Grog12 CBMod CB Mods Premium Member

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  3. Charc

    Charc Well-Known Member

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    Grog, is this necessary? I just found the VGA, E-net, DMX, and 6 pin (RFU?) connectors in the house.

    Should I assume something was installed in the system to allow both data inputs? Should I be checking specification sheets?

    I'm not positive how the e-net is helpful, which I assume runs from booth to house. The VGA I assume runs from booth to house, which would be helpful for a designer... sorta... if we had one... or an extra monitor... The RFU... I'm not sure why that needs to be in the house, and I assume that runs from booth to house. The data I'm assuming runs from booth & house to dimmers...
     
  4. Footer

    Footer Senior Team Senior Team Premium Member

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    Odds are that VGA connection is dead, was probably in the pannel when it was installed. Ethernet is great if you have SN110 nodes.

    You can merge DMX, its gets to be a pain but is doable. Do a search, it have been discussed before. Do a search for hight takes precedence.
     
  5. Charc

    Charc Well-Known Member

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    VGA is dead? Why would it be dead?
     
  6. Footer

    Footer Senior Team Senior Team Premium Member

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    Not hooked up, Sorry. People LOVE to put in vga connectors in panels, but when they go to install they rarely ever run copper to the plug. Could be they did, but I doubt it.
     
  7. Charc

    Charc Well-Known Member

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    I bet it's hooked up. I just don't see a use for the E-net to the middle of the house... or the RFU... maybe the board... But, the VGA could be useful for running video for a projector if we ever mount one in the canopy.
     
  8. Footer

    Footer Senior Team Senior Team Premium Member

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    What runs from your board to the dimmers? DMX or ethernet? Its probably for a tech table, not as an output. Strand has been specking ethernet everywhere since the roll out of the 300/500 series.
     
  9. DarSax

    DarSax Active Member

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    The reason for the RFU is that in case the designer is sitting in the house, designing, he/she can use the RFU as wanted.
     
  10. Charc

    Charc Well-Known Member

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    What is for the tech table? E-net? I guess they didn't realize we have wireless internet everywhere? That makes sense though. The e-net only runs between the house and booth. The RFU, I'm still not sure about... I'd rather the PDA based RRFU style thing.
     
  11. Charc

    Charc Well-Known Member

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    Right, but I mean given the hierarchy of our H.S. theatre, it's a feature that won't ever be used. And at that point, why not just get on coms and let the boardop do it?
     
  12. beltsvillecrucib

    beltsvillecrucib Member

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    In all probability the E-Net is Booth to house to allow an external view of the channel levels for the designer sitting in the house, not as a line to run internet. RFU as Dar said.

    As far as the DMX port goes it could be a line to the dimmers; touring shows sometimes like to keep their desk on the floor. I'm not really sure though.

    Edit: RFU could also be for someone to sit in the house during focus and the ME can call out channels to them, or if the ME likes to sit in the house and do it.
     
  13. icewolf08

    icewolf08 CBMod CB Mods

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    Here is the most logical reasoning:
    VGA - For a presenter in the house and a projector in the booth, though could be used for remote video for the console.
    Ethernet - Either for a remote video node (SN102) or so you can run the facepanel from the house while leaving the CPU in the booth (just don't plug the facepanel ethernet into any standard network hardware, it will fry them).
    RFU port - It is darn useful to have one of these in an FOH position!
    DMX - depends on where it is connected. However, i would assume that it was intended for a tech-table setup.
     
  14. JD

    JD Well-Known Member

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    DMX combo is not that easy. First, you have to ask yourself if you are just switching from board A to board B. If this is the case, the data switch Grog pointed to will work ok.

    BUT, if you are trying to combined the output and run both boards at the same time, things get tricky! Doug Fleenor also makes that type of product but it's expensive. The reason is that it is actually a computer that stores the DMX values from each of the boards, and then reads them out based on how you program it to do so. For example, lets say you are running a straight dimmer board and a separate mover board. If the channels do not overlap then the processor will simply correct the timing difference of the two DMX sources by storing the values in registers and reading them out at one timebase to your DMX instruments, ignoring the 0's from the second source. Things get a bit tricky if you have both boards producing an output on the same DMX channel. Now the unit has to decide which value to listen to: The higher value? The newer value? Only board A? Only board B?
    You get the point.

    I kind of like having a separate mover board, but my own answer is a lot cheaper- Run a second cable! Many boards have provisions for bridging with a midi interface for blackout cues etc
     
    Last edited: Apr 8, 2008
  15. Grog12

    Grog12 CBMod CB Mods Premium Member

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    Thanks to JD for getting to the longwinded answer before I had to!

    RFU isn't just for Designer manipulation, but so he can see levels without having to ask the LBO what they are at...and they're great for focus/troubleshooting/dimmer check.
     
  16. Flyboy

    Flyboy Member

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    Thanks to Grog and JD, that's exactly what I was looking for. I just wanted to know if there was a switch that would go between a primary and backup board. No real reason, I guess, but for sheer curiosity. Thanks again.
     
  17. David Ashton

    David Ashton Active Member

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    I often use a Showtech NL merge unit,costs around $300 and will merge either two desks on the same channels HTP or consecutively at a point you select,I have never had any problem with it, although I don't use it very often when I do it can save the day.
     
    Last edited: Apr 10, 2008
  18. church

    church Active Member

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    You may also want to check out Luella Enterprises at

    http://www.luellaenterprises.ca/

    I have one of their Merge circuits it works great and is very reasonably priced much less than a Feenor unit. I don't use it very often but as David said above sometimes they are just the thing to save the day or allow you to do something you just can't do otherwaise.

    The Luella unit takes the output from both consoles and combines on a highest takes priority basis. I use it for variety show type stuff where you haven't seen any of the show before and you have a mix of bands, singers etc. (best not to ask how I get into doing some of these things). Anyway I program one board for bands including a sound feed to synch chases and the other board for the other stuff. This allows me to swap seamlessly between boards and even to use both at the same time.
     

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