For beginners in stage lighting, one of the ideas that can be baffling is how to wire up all of your fixtures. Back in the “old days” you simply ran control cable to your dimmers, and power out to your conventional fixtures. It was pretty simple overall, with no “settings” or configuration required on your lights.
Today, however, this all gets to be a little more complicated! Most, if not all fixtures in a modern lighting rig require DMX signal, and so it can get a little confusing when you’re trying to manage it all.
Check out the video below for the basics, and then we’ll talk go a little deeper into detail:
When working with a lighting console, whether it’s a PC-based or hardware, the console will come with a DMX output. A DMX output sends out a signal to communicate with lighting fixtures.
The Daisy Chain
The daisy chain is a simple wiring method where you wire each fixture looping out of the previous fixture to create a line of fixtures connected back to the console.
Example: Let’s say you have 4 LED Fixtures. Most fixtures will have a DMX input and a DMX output. From the console’s DMX output you will wire into the fixture or device’s DMX input and wire out via the DMX output to the next fixture or device.
So, what happens when you reach the last fixture? You will have a DMX output that’s not being used.
The “spec” requires that you’ll then use a DMX terminator to stop the data from reflecting. But in most situations, this will not be needed.
DMX Terminator: Here’s one if you need it!
32 Fixture Rule – DMX only allows you to connect up to 32 fixtures in a single daisy chain for signal strength. Sometimes, depending on the fixtures and cable length, this number is less (or more).
Realistically most people recommend only setting up 16 – 20 fixtures or devices in a Daisy Chain. This is because some fixtures may be “heavier” or “lighter” on the DMX Line.
Devices would also include a Dimmer Pack. A dimmer pack can connect 4 – 8 lights but still only count as one device in the daisy chain.
To get around the 32 fixture rule, you can split your DMX signal and create multiple daisy-chains.
In the simplest form, a DMX splitter takes the DMX output and just copies it multiple times. A DMX Splitter can also be known as an “optical splitter” or even an optical isolated splitter.
Splitting your DMX also can help you make your cable runs cleaner, and isolates different runs of fixtures. Check out my favorite DMX splitter here.
A DMX splitter can also protect your console in the event that you connect a faulty light up to it! I recently was talking with another lighting designer, and he shared with me a story of a client who fried a $15,000 lighting console because they hooked it up to a cheap LED fixture.
The LED fixture was not a name brand, and something went wrong internally, sending voltage down the DMX line and killing the DMX chip in the console. Not cool, and an inexpensive DMX splitter would have taken the heat instead of the expensive console, had they used one!
Some splitters will feature a 3-pin or 5-pin for each output. When a splitter has both 3 and 5-pin on one labeled output, you will need to either choose between a 3-pin or 5-pin, you cannot use both!
If the splitter’s plugs are labeled separately on the output, then you are able to use each plug if needed.
When a Fixture Has 3-Pin and 5-Pin Inputs and Outputs…
When you have a fixture that has both a 3-pin and 5-pin input/output it is the same principle as working with a splitter.
You can have 3-pin output and 5-pin input or vice versa but you cannot have 2 inputs and/or 2 outputs.
You can’t use 3 and 5 pin DMX jacks on fixtures as a split!
DMX lights these days can take up more channels than ever before, and when you need more than 512 Channels you’ll need to start a new DMX universe.
A DMX universe is simply a new, fresh set of 512 DMX channels to control your lights.
When you have multiple universes your console will note these Universes as DMX 1, and DMX 2 (and 3, and 4…) and the address will show this as well in the patch section. Some consoles will use letters instead of universe numbers (i.e. A, B, C…)
You can just wire the universes separately, it’s really that simple!
Just remember to keep the fixtures and devices on the desired universe only. You cannot mix these, as regular DMX lights can’t understand the difference between universes and will, therefore, do the wrong thing!
When your console has multiple universes, you can “zone” your lighting rig by different universes to stay organized keep your wiring simpler.
Also, DMX splitters can’t span multiple universes, though some allow you to input 2 universes and choose which ports you want to assign to each output.
As I mentioned in the video above, DMX is always changing, and we’re always seeing more and more new lights that have even more channels then before.
Some lights today can take networked DMX in natively, and don’t even use DMX cables at all! As we move further into the future, this will probably become a larger part of our lighting!
Still, even with regular DMX fixtures, it’s becoming more and more rare to need DMX splitters – as we move forward and prices continue to fall, we’ll be seeing more shows move to use Art-Net and sACN nodes instead for those lights that require “old-school” DMX.
I hope you really enjoyed this article, and that it helps you to create great lighting. There’s nothing worse than hitting a technical hurdle in your lighting!