DMX Universe & Address Planner.

A DMX universe is a single DMX512 data line carrying up to 512 individual control channels. Every dimmer, colour or movement parameter on a lighting fixture uses one or more of those channels, so once your fixtures need more than 512 channels in total you have to split the rig across a second universe. Modern consoles and lighting networks (such as Art-Net or sACN) simply run multiple universes side by side over a network cable.

Add up the channel count of every fixture (channels per unit times quantity) and divide by 512, then round up. The catch is that a fixture should never straddle two universes, so if a fixture would cross the 512 boundary it is pushed to the start of the next universe, which leaves a few unused channels at the tail of the previous one. This planner does that boundary handling for you, which is why the universe total can be slightly higher than a flat channels divided by 512 sum.

The start address is the first channel a fixture listens on; it then reads the next few channels in sequence based on its channel mode. Every fixture in a universe needs a unique start address with no overlap, or two units will respond to the same commands. The convention is to leave a small gap or set addresses end to end in order, which is exactly the clean patch list this tool generates for you to copy onto your console and fixtures.

Most modern LED and moving-head fixtures have several DMX modes, for example a basic 4 or 8 channel mode versus an extended 16 or more channel mode with fine control and extra effects. Always enter the channel count for the exact mode you have set on the fixture, since the same light can occupy very different amounts of a universe. If you are unsure, check the fixture's menu or its manual, as the mode on the unit must match what you patch.

Small rigs of a handful of LED pars in a low channel mode often fit comfortably inside a single 512 channel universe. You typically cross into a second or third universe once you run a lot of fixtures, use high channel pixel or moving-head modes, or add pixel-mapped LED that consumes channels quickly. Planning the universe count early tells you how much DMX cabling, splitters or network nodes the rig will need before you get to site.