DMX512 wiring

DMX512 is the classic wired protocol: one cable, one universe of 512 channels, each a byte from 0 to 255, refreshed continuously. OmnaDMX receives it and acts on it according to the current operating mode.

Wiring

Bring DMX in through a standard isolated DMX/RS-485 input stage. Data+, data−, and ground go to the transceiver, and the transceiver to the controller’s DMX UART pins (check your board’s pinout). Wire it as a normal DMX run: daisy-chain, single home-run, and terminate the last device with 120 Ω. Skip the terminator and you get intermittent flicker or dropped frames, usually worse the longer the run.

Selecting DMX512 as the input

In the DMX tab, set the input source to DMX512. Only one input source is live at a time, so choosing DMX512 releases Art-Net and sACN reception, and the reverse. Output is independent of this (see below). Switching is instant and safe.

Start address, and when it matters

The start address is a 1-based offset into the 512-channel frame that tells the device where its channels begin on the desk. It applies to the modes that read one universe:

• DMX Dimmer and DMX Motion take a small per-element footprint starting at the address. What each channel means comes from the fixture profile.
• Single-universe DMX Pixels begins pixels at the start address, 3 channels each for RGB or 4 for RGBW. Watch the footprint: a strip that runs past channel 512 gets flagged. See Multi-universe addressing.

Pattern mode takes no desk input, so the start address does nothing there.

Input and output are independent

Receiving DMX512 doesn’t stop the device sending Art-Net or sACN out, which is configured separately on the System and Strips tabs. Wired DMX in, network pixels out is a common, valid bridge.

Next: Art-Net setup.