Lighting systems controlled by Digital Multiplex (DMX) require adherence to strict instructions. DMX is the universal standard for theatrical lighting control, and uses a binary code system to assign each lighting fixture a digital "address." A main DMX controller sends digital instructions to addresses assigned by the operator, causing the light assigned to that address to function as desired.
Create a Written Plan
The first step in working with your DMX lighting system is to create a written plan. The plan includes a list of all lighting fixtures, their function and how often they are used during the show. The plan should also include a diagram of each lighting fixture and its placement on the stage. Since each fixture will be assigned a DMX address, group together and assign lower DMX addresses to the lights most frequently used, and assign higher addresses for occasional use lights. This will allow you greater flexibility and makes organizational sense when sending instructions to fixtures from the controller.
Create several plans and diagrams, and try different ones until you find one or more that work well. Set-up your lights in a basement or garage if possible, and practice working with the equipment and tweaking plans if needed.
Understand DMX Set-up
Setting up DMX hardware set-up is very simple. Each DMX fixture is connected in "daisy chain" fashion, beginning with the DMX controller. The location of the fixture in the DMX chain has nothing to do with its DMX address, allowing you to set-up lights in any arrangement that suits your need. Mount or install all DMX fixtures according to your placement diagram, and provide them with electrical power. Plug a DMX cable into the output of the DMX controller, and plug the other end into the input of the nearest DMX fixture. Take another DMX cable and plug it into the first fixture's output, and into the input of the next fixture. Continue connecting fixtures with DMX cables in this "input to output" manner. When you've reached the end of the chain, the set-up is complete and it's time to assign DMX addresses.
Assign DMX Addresses
Assigning DMX addresses is one of the more confusing aspects of the DMX system. DMX is designed to operate up to 512 channels, with each channel performing one function. Depending on the light fixture, one or more DMX channels will be used according to the specific functions and needs of the fixture. The DMX controller recognizes and assigns the proper number of channels to the fixture. Regardless of the number of channels used for a fixture, each fixture is assigned one DMX address.
Each DMX fixture is equipped with numbered changeable "DIP"(dual-online package) switches used to assign that fixture its DMX address. DMX is a binary code system that starts with the number "1". Designate one of the fixtures as number "1", and push the number "1" DIP switch to the "down" position. This light will now operate on channel number one of the controller. In binary code, the next number in line will be twice the value of the previous number. Set the DIP switch of the next fixture to "2,' the next fixture to "4," and continue doubling numbers for each fixture. This is a very simple example, assuming that your fixtures are using one DMX channel each. Consult the owner's manual of your fixture to determine how many channels it will use, and it will include any specific addressing instructions. Study published DMX address tables to get a clearer idea of how DMX addressing works, as every set-up will be slightly different.
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