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This tutorial shows you how to calculate how many DMX channels will be needed in a project.
Date: 08/2014
Introduction
Nowadays, LED installations are getting bigger and bigger and it is common to control a lot of LED DMX fixtures. Especially, when you want to control a project with MADRIX, it is useful to know how many DMX channels will be controlled in total.
DMX Channels And DMX Universe
1 DMX universe includes 512 DMX channels. If you need more channels, it is necessary to use additional universes.
After your calculations, you will know two numbers:
1) the total number of DMX channels and
2) the equivalent number of DMX universes, which usually is also the number of required DMX lines.
Example 1
How many RGB 1-pixel fixtures can be controlled with 1 DMX universe?
1 DMX universe contains a maximum of 512 DMX channels. A normal RGB 1-pixel fixture uses 3 color channels to mix all other colors. These color channels are Red, Green, and Blue.
At the same time this means that such a fixture usually requires 3 control channels (one control channel for each color channel).
Control Channels Per Fixture:
1 pixel * 3 color channels = 3 control channels per fixture
Calculation:
512 DMX channels / 3 control channels = 170.66667 fixtures per universe
Now, we need to round that number down to 170.
170 fixtures * 3 control channels = 510 DMX channels
When we use 170 RGB 1-pixel fixtures, channel 511 and channel 512 would still be unused. Can we fit fixture #171 in there with its first two channels?
The answer is no, we cannot. If a fixture is included in a universe, normally the full fixture needs to be able to fit into that universe. Because of this, channel 511 and channel 512 are usually not used in case of RGB 1-pixel fixtures. Fixture #171 would not fit fully into the universe anymore.
Number Of DMX Universes:
From the beginning we knew that we only wanted to use 1 universe.
510 control channels / 512 DMX channels per universe = 0.99 universe = 1 universe.
We need to round that number because there are only complete DMX universes.
Result:
That means you can control a maximum of 170 RGB 1-pixel fixtures (if each fixture needs 3 control channels).
Example 2
How many RGBW 1-pixel fixtures can be controlled with 2 DMX universes?
A normal RGBW 1-pixel fixture uses 4 color channels to mix all other colors. These color channels are Red, Green, Blue, and White.
Control Channels Per Fixture:
1 pixel * 4 color channels = 4 control channels per fixture
Available DMX Channels:
2 universes * 512 channels per universe = 1024 available channels
Calculation:
1024 available channels / 4 control channels = 256 fixtures in total
256 total fixtures / 2 available universes = 128 fixtures per universe
Number Of DMX Universes:
2 universes
Result:
You can control a maximum of 256 RGBW 1-pixel fixtures (if each fixture needs 4 control channels).
Example 3
You might want to use 300 pieces of RGB LED tubes. Each tube features 16 pixels. How many DMX channels will be needed?
Control Channels Per Fixture:
16 pixels * 3 color channels = 48 control channels per fixture
Calculation:
48 control channels * 300 pieces = 14,400 DMX channels in total
Number Of DMX Universes:
14,400 DMX channels / 512 channels per universe = 28.125 universes = 29 universes
Result:
You will 14,440 DMX channels / 29 DMX universes for such an installation.
Example 4
You might want to use 1) 100 pieces of 32-pixel RGB LED tubes as well as 2) 200 pieces of 16-pixel RGBW LED tubes. How many DMX channels will be needed?
Control Channels Per Fixture:
1) 32 pixels * 3 color channels = 96 control channels per fixture
2) 16 pixels * 4 color channels = 64 control channels per fixture
Calculation:
1) 96 control channels * 100 pieces = 9,600 DMX channels
2) 64 control channels * 200 pieces = 12,800 DMX channels
3) 9,600 DMX channels + 12,800 DMX channels = 22,400 DMX channels in total
Number Of DMX Universes:
22,400 DMX channels / 512 channels per universe = 43.75 universes = 44 universes
Result:
You will 22,400 DMX channels / 44 DMX universes for such an installation.
Congratulations! The examples above should have shown you the basic calculations when it comes to the total number of required DMX channels.
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