The articles that follow, are intended to teach you how to set up, and control your DMX fixtures with a 12 fixture controller (software will be in future articles). The reason I am describing the 12 fixture controller, is that it is the most common controller in the industry. Once you understand this controller, you will be able to translate your knowledge to other controllers of different designs, and they will still make sense. This controller will handle up to 12 fixtures (there’s a way to cheat and get more), each with up to 16 control channels. This will all be explained in this, and following articles.
Most of the light fixtures used by DJ’s and bands, have fewer than 16 control channels, so this 12 fixture controller is perfect for 99% of “OUR” applications. I like to mention “baby steps”, when I teach DMX controllers.
But, let’s start out with, what exactly is DMX?
DMX stands for “Digital Multiplex”. Or, another description is “DMX512”. The “512” stands for 512 channels of control. DMX 512 is a “protocol” (electrical set of instructions), that DMX fixtures understand. NOTE: not all DMX equipment, is a “light” fixture. The standard was developed in 1986 by the USITT (United States Institute for Theatre Technology). It allows for one cable to control 512 channels of operation by using a digital signal.
Think of it as 512 small wires inside one cable. In actuality, DMX cables have only three wires (back in 1986, the first cables had 5 wires), but by viewing it this way, it makes it easier to comprehend. DMX cable is different than XLR cables, even though many say you can use XLR. The resistance and shielding is different, and permits the digital signal to move down the cable differently.
The real cable, with 3 wires, allows the flow of “digital” packets of information, that is separated into information, that each fixture understands with the use of an “address”. Think of it as your letter carrier delivers your mail to you, only with your address on the front of the envelope. Addresses are arranged from 1 to 512. Each fixture in your DMX collection has an address switch, somewhere on its housing. Some are “dipswitches” and some use digital push buttons to set it’s address (more on that in later articles).
So, think about the dimmer light in your living room, or over your kitchen table, with the dimmer switch on the wall. As you move the switch or knob, your light bulb gets brighter or dimmer as you move the switch. DMX fixtures operate with this same concept. Your ceiling light fixture is utilizing ONE control channel with the dimmer switch. When using DMX fixtures, you have 512 channels of control, simply by moving a “slider” switch on the control panel. So, in essence, you can independently operate 512 fixtures if they have only one control channel. But, with DMX, you can assign channels and get as many fixtures as you want, if you copy channels in various fixtures (more on that later too).
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