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Thread: Combining ILDA and DMX signals on same cable?

  1. #1
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    Default Combining ILDA and DMX signals on same cable?

    I am considering the option of adding DMX signals on 3 spare wires of the same ILDA cable I use for connecting a controller to the projector. Does anyone know of any signal problems this might cause?

    Also, for those of you who have been doing this a while, what it the maximum RELIABLE cable length between the controller and projector using ILDA standard wiring with a typical commercially-available DB-25 cable?

    Thanks!
    RR

    Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.
    1979.
    Sweet.....

  2. #2
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    Those are two good questions. I just got a set of the scanco 20s with the DMX board from SELEM and want to try and incorporate them with a greeny into my projector for some extra beams. It'd be nice to be able to use one cord for signalling. How do you plan on getting the DMX signal on the ILDA cable from your DAC?
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

  3. #3
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    Basically, I'm trying to limit the number of cables between the controller and the projector, and maximize my capabilities and options.

    I'm going to be using a Pangolin FB3 (with USB and DMX daughterboards) as the DAC for my first projector. My idea is to mount it in a separate control box with it's own ("wall wart") power supply. The control box would contain a DB-25 connection for the ILDA cable, and a XLR connector for adding an external DMX controller console. Internally, this will feed both the FB3 DMX input, and a DMX thru-connection on the ILDA cable leading to the projector. At the projector, the DMX signal could be broken out and routed to additional DMX control boards for activating actuators, effects, etc.

    Provided mixing signals on the same DB-25 cable is not an issue, this would present several advantages:

    * Requires a single signal cable to the projector, instead of separate DMX and USB cables.
    * Option of easily switching between DMX-only control or computer control throught the FB3 DMX and USB connections.
    * Can incorporate ILDA "interlock" capability as required for projector certification.
    * Easily add MIDI control option through the attached DMX controller (I'm planning on using an Elation DMX Operator)
    * Ability to switch to a full ILDA-compliant control system (LD2000) down the road without requiring a projector rebuild

    Now, if the cable length isn't an issue, all I have to do is get home so I can try out my ideas!
    RR

    Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.
    1979.
    Sweet.....

  4. #4
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    I have used 35m long cables before. I did not experience any problems.

  5. #5
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    mixedgas is online now Creaky Old Award Winning Bastard Technologist
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    Ilda standard has a bunch of pins labeled user1 user2 user3 etc
    usually they are used for color on pcoams, but if you like, as long as your signal source can switch em off when connecting to somebody elses machine, (boy, did we need THAT at selem) your welcome to run DMX.
    There once was discussion of a few pins becoming the serial data, but like all things in a standards comittee, they needed a year to ratify DMX, so it didnt get included, although two pins were going to be reserved for serial.
    So in your console, cable splice, whatever, put a way to unplug or terminate DMX levels and your F.I.N.E. fine :-)

    my cable is 60 feet, and running differntial is just fine.


    8,9,10,11,21,22,23,24 are fair game.

  6. #6
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    Hi guys,

    I'm not yet an experience laserist, but I'm working with DMX daily. You can't simply run a DMX signal through an ILDA cable. It may work, but you can get strange responding fixtures and errors in situations. DMX should be connected by 110 Ohm cable, with a DMX negative, DMX positive and a shield. The end of the DMX-line (that is, in the DMX Out of the last fixture) should be a 110 ohm terminator (between pin 2 and 3).

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