I teach Drama, and recently acquired a new ETC ColorSource 40 light board as we begin to transition over to LED (a few new lanterns a year).
I don't want to waste my old board, especially because I teach 8th Grade to 12th Grade, and I see the old board as a valuable learning tool.
My question is: Is there any "splitter" that would allow me to ALTERNATE which board I use to control the lights?When an 8th or 9th Grade class is doing tech, I want them to use the old board, while experienced students in older classes would use the new board but I don't want to have to manually be moving the DMX cable back and forth between the two systems every time class changes. I would NEVER have both system powered and running simultaneously. I just want to be able to power down one, and power up the other, and vice versa.
Can this be done?
Yes, this should probably be okay. Before lighting systems went Network, many systems were designed with 2 or more DMX Input plates, such as one in the lighting booth and one down in the audience area…
If your college has the wherewithal, a simple Y cable could be made up with a double pole double throw (DPDT) switch changing over the two inner cores of the cables should do the job.
Perhaps someone from ETC can tell us what the output impedance of a switched off console is, but if it is high then a simple Y microphone XLR splitter would probably do, with 5 to 3 pin adapters where necessary, providing the cable runs are not excessive. What would stop this working is one desk loading the other or signal reflection from the unused branch causing erratic fixture behaviour.
A simple Y connection is a bad idea.
E1.11 DMX requires transmitters to terminate (and optionally ground) the line, while E1.20 RDM requires RDM controllers (like ColorSource) to have an RDM controller termination network which biases the line to prevent noise when waiting for an RDM response.
Connecting two compliant consoles at once - even if one is physically turned off - will create a multiply-terminated DMX/RDM line, probable ground loops and all the attendant signal quality issues.
All technical details aside, this is in an educational setting which makes it doubly important to be strict about compliance.It's important to teach "best practice", even if it's usually possible to "get away" with less.
A DPDT switched "crash box" as suggested above is the simplest solution, and very cheap.
- I call them crash boxes because they make a brief nasty flicker when switched "live". I don't think that matters for this OP!
There are also a variety of DMX mergers like the one Arnof linked to, and ETC's Gateways can also be used as DMX mergers.A DMX merger solution allows a "live" handover of control between consoles, or even to share control.