So, while thinking of 512 wires (actually only 3... the software converts all of the packets into a binary signal that gets sorted out in the fixture), think of that one slider having 255 possible positions along that slider. So, as you move the slider into any one of the 255 positions, you are changing something within that particular channel on that fixture. When they build fixtures, they pre-set "parameters" within each fixture, to respond to the input signal from the controller.
Let's say, you have a 4 channel scanner. Channel one may be "pan". That is the mirror moving back and forth. Channel two may be "tilt", with the mirror moving up and down. Channel three may be shutter and lamp. and channel four may be color and gobo.
So, if you have the fixture set to the correct "address", you will be able to turn the mirror in any position you want with channels one and two, and turn on the lamp to your desired color with channels three and four. Keep in mind that every fixture has different parameters for each channel and function, so, every fixture responds differently depending on which slider you are moving. The important thing to remember is that each channel parameter changes only that design function in 255 different possibilities.
Here's what I mean by that: lets say that you want to move the mirror to the center of the dance floor. So, you'll have to move the first slider to correspond to the horizontal position, and the second slider to a vertical position. As you move slider one, you will notice the mirror moving back and forth. Lets say that the center of this dance floor requires position 172 to line up with the center of the floor, but you may notice that the light isn't on, and you have no idea where the light will shine out in the room. So, turn on the lamp slider.
I like to find the lamp channel slider first, so I can visually see what the light display is doing. As you move slider three, you are changing something on the lamp channel. Depending on that particular fixture, you might have lamp intensity, or strobe (for example). Now that the lamp is on, and you have moved channel one to position 172 along the slide path, you can then bring slider two to a position that brings the light from the wall, down onto the dance floor... lets say position 88 on channel two. Now you want to change it from a white light to a red light. Moving channel four will change the colors. On your instruction sheet, you will notice the "parameters" of each channel listed something like this: CH. 4 - 0-50 white; 51-86 red; 87-125 blue; 126-198 green; 199-255 multicolor mode. If you desire a red light in the middle of the dance floor, you'll have to set channel four at 51-86 along the path of that channel slider. You'll notice that the moment you hit position 51 the white light changes to red, and stays red until you hit position 87. When I'm programming a show, I like to go "mid-way" between ( pick "70"), so that a slight bump of the slider won't change the color.
Next lesson will explain setting addresses...