Demystifying DMX

Demystifying DMX

So you just bought some lights for your show and you want to control your light but what’s with all the buttons and why doesn’t it work when you plug things in?

Don't worry, you won’t need a degree in computer programming. Today I’ll give you a very basic understanding how DMX works and how to set up a basic System.

1. Set up

Let’s imagine you have four wash lights, a controller and four cables.

Your controller has an XLR DMX out. It looks like a mic input in your audio mixer but a DMX cable attaches opposite where female jack is out and male jack is in. (Oh boy here we go … Stay with me… DMX ports are marked in and out).

Your light has both in and out DMX ports.

If you bought DMX cables with your system, use them as they are rated for DATA rather than AUDIO. IF not, you can use MIC cables with few problems until you are using a lot of lights.

Now, run a cable from your controller to a light’s DMX in. Take another cable and run it from DMX out on that light to DMX in on another light. Again to the third light, And again to the fourth light.

Cool … We are set up.

2. The DMX Controller

Don’t worry about all the buttons for now. We will be using the sliders, the a/b switch, and a fixture switch.

I’m including a picture of a standard DMX controller. Yours may look different but the concept is the same.

Each Slider is a channel. In our case we have channels 1 through 8. Using the a/b switch we can access 8 more channels, 9 through 16.

We’ll get into the fixture switches some other time.

3. Setting up the lights.

We don’t need to set up the controller. The controller only sends signals. The lights receive and react to the signals.

Different lights have different functions. The wash lights we chose have four colors: Red, Green, Blue, and Ultra Violet.

RTFM: I hate saying read the manual but we have to read the manual, at least the important parts.

Find how to adjust the settings on your light and also find the DMX channel chart (see below). You’ll need to tell the light to look for DMX signals and what channel to receive them on. Oh yeah, and how many channels the lights will use. I’m going to use the four channel mode or one channel for each color.

My Lights are four color LED wash lights… ez peazy.

On my light I’ll press the mode button until I see the letter d and a number in the display. (d.xxx). Use the up and down keys until it says d.001. Cool, channel one. Now I’ll press the set up button and choose the four channel mode (ch4). Done, the light is set up, one color per slider. Let’s try it.

4. Back to the controller.

Press the fixture 1 button. A light will show you that it is engaged. Make sure the a/b switch is set to "a". Move the first channel slider up. The red LEDs on your light should come on. Slide it back down. Now slide the second channel, Green. Third slider, Blue and Fourth slider, UV. Now try the first and third channel, purple. Now try the first and second channel, amber.

Now we’re rockin’!

5. Adding a second light

Go to a second light and set it up the same way as the first. (d.001 and ch04). Now both lights will react the same way. There’s half your stage.

6. Now the fun starts. The third light.

On the third light we want the colors to be different from the first two so we will choose a different DMX channel.

We used the first four sliders on the first two lights. The next empty slider is five. Change the DMX channel to five. (d.005 and, of course, ch04). Slide all the channels down and then slide channel five up. Red! Six will be green, seven, blue and then eight UV.

Go to a fourth light and set it up the same way as the third. (d.005 and ch04). Now the third and fourth lights will react the same.

Enjoy the show. You are set up.

This is a basic set up designed to get an understanding of DMX channels. Your lights might only have three colors. Some LED lights have as many as six. The setup is the same only the numbers of channels are different. Just set the starting channel to the next empty slider.