When you hear someone talking about DMX, what comes to mind? Are you thinking of multi-platinum album recording artist Earl Simmons. He’s professionally known by his name of “DMX.” While you might think of him, first, lighting professionals around the world think of DMX-512 and know it as a foundation to theatre lighting and control. As defined by Wikipedia, DMX512 is a standard for digital communication networks that are commonly used to control stage lighting and effects. Shows all over the world rely on DMX networks to present their lighting designs.
DMX512 is synonymous to DMX. DMX512 is the official name for the protocol, while DMX is a quick “nickname” of sorts to refer to it by. The reason why “512” is included in the name (DMX512), refers to the amount of addresses that one DMX line, or universe, can hold. That is getting ahead of us, though. Let’s start from the beginning.
In a typical DMX line, you will have a few different components. You typically will start with a control console that will give different values to DMX addresses to control the end component. The end components could be electrical dimmers for incandescent lighting, moving head lighting fixtures, LED lighting fixtures or special effects devices such as fog or haze machines. Moving head lighting fixtures are very sophisticated lighting fixtures that have many controllable attributes. You can control these attributes through manipulating the DMX addresses assigned to the fixture. Some of these moving light fixtures can have upwards of 50 DMX addresses to each lighting fixture. That would mean a maximum of 10 lighting fixtures could be used off of one lighting console. What about when I go to a Coldplay concert and see the hundreds of lighting fixtures being used for the concert? Does that mean that there is a separate lighting console per 512 addresses? The answer is: No. While only 512 addresses can be controlled on one line of DMX, there are control consoles available that can control more than one line, or universe, or DMX data. How many universes are controllable? Well, a GrandMA 2 Full-Size console, made by MA Lighting, can control up to 256 DMX universes with MA NPU. That’s 131,072 addresses! Or, 4,854 Martin Quantum Profile moving light fixtures! That’s a lot of lights.
DMX can be carried in multiple ways. The most common is DMX 5-pin cable. There are 5-pins and typically only 3 pins are used, the other two pins were put aside for “future use.” If you are just transmitting control data from a console to your fixtures, DMX 3-pin cable is typically just fine. The other way to transmit DMX data around could be through DMX nodes. Companies such as ETC and Pathway Connectivity Solutions have products that with take your DMX universes and distribute them around via Ethernet cable and DMX nodes. The nice thing about these nodes is that you can change any DMX node on your network at any time to output a different universe. For instance, if you are a touring house and you have a catwalk DMX node that is setup for Universes 3 and 4, but a group comes in and needs Universes 2 and 8, you can go into the companies’ program on the network and change the output of that DMX node to universes 2 and 8. Instead of having to cable to your catwalk, or figuring out where you will tap into those universes from, with a couple of clicks you are able to change the DMX node to meet your needs. In the future, likely, they will go a step further to eliminate the need for the DMX nodes and you will take your ethernet cable and plug directly into the lighting fixture and addressing it with an IP-address. The protocol for DMX directly over ethernet is called Art-net.
To review, DMX is a protocol used to typically transmit lighting data from a control console to the end devices. There are 512 addresses in one DMX universe. These addresses can be transmitted over 3 or 5-pin DMX cable or over ethernet via DMX nodes or directly with just the ethernet cable. So the next time you hear people talking about DMX, don’t automatically assume its about the rapper. It could actually be about DMX512 (its been around longer)!
Sources
https://en.wikipedia.org/wiki/DMX_(rapper)
https://en.wikipedia.org/wiki/Art-Net