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DMX Splitters??

Discussion in 'Lighting and Electrics' started by lazor, Jan 9, 2009.

  1. lazor

    lazor Member

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    I was working in a different theater last week and we started talking about DMX splitters and how they would be fairly useful in my theater. I have two FOH trusses on motors that are easily lowered for hang and strike. On these trusses I have Varilites and traditionally have used I-cues as well. It would be great to have separate chains of DMX for the Varilites versus the I-cues or perhaps in the future Gobo rotators, effects wheels, or color scrollers. Currently there is one DMX cable run to each Truss. Therefore, I'm looking for a small DMX splitter to sit on each truss with two to four out-puts. Also, since I'm in the market I also would like a splitter on stage where there is only one DMX input for the entire stage and all battens. This one could be larger but would be nice if it could be pipe mounted to the permanent side pipes before going to each batten.
    Would love input and to start a dialogue about DMX splitters
     
  2. icewolf08

    icewolf08 CBMod CB Mods

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    Let me ask a couple questions. Why do you need to split the signal on your FOH trusses? The Vari*Lites, ICues, and any other DMX toys don't care if they are daisy chained or on separate lines. It requires the same amount of cable either way, and if you run separate lines then you need more terminators. I only run one DMX line to a position unless I need more than one universe, in which case you actually need multiple lines and not a splitter.

    As for on your deck and overhead battens, I would suggest putting an opto in on the deck and running a line up to the grid with another opto on the grid. Then from the grid you can make drops to any batten that needs data. This will keep the cable clutter to a minimum as you won't have to lift data from the deck to battens.

    As far as splitters go, the Doug Fleenor gear is kind of the industry standard. A little on the pricey side, but it is rock solid. I have also had success with the Elation DMX Branch 4 splitter, much less expensive, bluky, and not as rugged, but it works.

    The other way to go depends on what console you are running. Most newer consoles allow you to output data over TCP/IP on Cat5 cable to proprietary nodes or gateways. With Strand you have the N21 show net nodes, with ETC you have the Net3 DMX gateways, HOGs have one, GrandMA has them, etc. So you could run Cat5 from your console to your lighting positions and then install nodes. The beauty of nodes is that they can be configured to output any range of 512 addresses per output, so you can configure them however suits you. Also, Cat5 is much cheaper to run than DMX and you can use standard network gear to hook it all up.
     
  3. MNBallet

    MNBallet Active Member

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    I've owned the Elation branch-4 for several years with no issues from it.
     
  4. theatretechguy

    theatretechguy Member

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    Same here. It's a bit large, but it has a hole to truss mount it.
     
  5. KeeperoftheKeys

    KeeperoftheKeys Member

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    DMX (officially) only allows for up to 32 devices on one (unsplit/buffered/reinforced) line, and that is if all your cables are in optimum condition and not too long...
     
  6. avkid

    avkid Not a New User Fight Leukemia

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    Not quite.
    It allows for 32 "units" of load.
     
  7. icewolf08

    icewolf08 CBMod CB Mods

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    At the same time, given that most moving lights average around 30 DMX channels, you can only put 17 on one universe thus requiring multiple data runs before you even get to that limit. You would have to run a lot of low DMX channel count devices from one position to get to that limit seeing as most devices other than moving lights (scrollers, irises, gobo rotators, etc) use a PSU that distributes power and data to the devices, thus 5 scrollers on one PSU really is only one device.
     
  8. mc2880

    mc2880 Member

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    The chroma-q 4play is a decent splitter and ready for a c-clamp.

    I assume since you have moving lights out there you'll have room to plug a splitter into a constant power source.
     
  9. dramatech

    dramatech Well-Known Member

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    I have 3 Elation splitters, and have modified two of them, by adding a 24 volt 12 amp power supply and changing the 3 pin connectors to four pin. That way I use the five pin for straight DMX runs and the four pin for scroller supply.
    I wouldn't purchase anything else.
     
  10. icewolf08

    icewolf08 CBMod CB Mods

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    I would be very wary of using a home brew scroller PSU, mostly on account of I bet it voids any warranty that the scroller manufacturer has. Besides, if I remember correctly, a 150W PSU from Apollo is about the same price as the Elation DMX splitter.
     
  11. dramatech

    dramatech Well-Known Member

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    Good call if your scrollers are in fact under warantee. I have 26 scrollers that I have purchased in damaged condition, a few at at a time. I have rebuilt each one to excellent operating condition. I have built 6 scroller PSUs and have built my own scroller cables from digital audio cable and zip cord. I volunteer at a community theatre, and buy the equipment with my own money and give to the theatre. If I did it any other way, we wouldn't be able to afford scrollers. In the ideal world of comercial theatre where there is a lighting buget, your comment is right on. I don't live in that world. Plus, I have been involved in engineering many of the comforts that you enjoy, such as the digital TV and photographic cameras, Low light vision devices and the surface wave filter, that makes cell phones possible. Theatre is my hobby in my retirement years. I'm trying to give back to my community with my engineering skills. My closing comment would be, don't do anything that would void a warantee or that is dangerous. If you have the skills, experiment a little as long as it is safe and won't cause anybody harm. That is how I learned my skills.
     
    JohnA and (deleted member) like this.
  12. SerraAva

    SerraAva Active Member

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    Another nice part about the Elation splitters is each output, 3 pin and 5 pin, has a DMX drive behind it. This means you can effectively use it as an 8 way split. However, there are only 4 separate isolated branches. This means that if something causes 5 pin output A to go down, 3 pin output A can go down as well since they aren't isolated.
     
  13. NeroCaesar

    NeroCaesar Member

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    I had 2 easy questions that i just wanted to clarify.
    Can you or would it be wise to run one universe to an iso splitter and then split one of the forks off with another iso splitter?
    If you were to split a dmx with an iso splitter 3 ways, could you put 20 devices on each fork and still be fine? (the total number of devices of course being over the theoretical max of 32)
     
  14. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Yes, it would not be unwise to use an opto-splitter on an output of another opto-splitter.

    Yes, you would be fine. Each output resets the "load limit."
     
  15. NeroCaesar

    NeroCaesar Member

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    Ahh that's what I thought Thanks.
     
  16. venuetech

    venuetech Well-Known Member

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    I have had a Enttec D-Split for anumber of years now without any issues. described as a "optical isolator/splitter" 4 outputs, two difrent models one with all 5pin out, another with two 3pin / two 5pin outputs.
     
  17. Chris15

    Chris15 CBMod CB Mods Premium Member

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    Just remember that the input of a splitter counts as a device in terms of loading calculations ;)
     

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