DMX512 sends every fixture's dimmer and color values down a single serial data line (RS-485, 250 kbit/s) by multiplexing them into one repeating frame: a break, a mark-after-break (MAB), a start-code byte, then up to 512 one-byte channel slots sent back to back. Each fixture is patched to a starting address and simply reads the N consecutive channels that belong to it — here each RGB PAR uses 4 channels: Intensity, R, G, B.
Bit time = 1 / 250,000 baud = 4 μs
Slot time = 11 bit-times (1 start + 8 data + 2 stop) = 44 μs
T_frame = T_break + T_MAB + (1 + N) × 44 μs (+1 = start code)
Refresh Hz = 1 / T_frame
- Fixture buttons — select which 4-channel block (DMX address) the sliders below edit.
- Intensity / R / G / B sliders — write raw 0–255 byte values into that fixture's channels; the beam and stage lighting update from the actual channel values, not from a shortcut color picker.
- Channels in use — a real console only has to transmit as many slots as are patched. Fewer channels means a shorter frame and a faster theoretical refresh rate; a full 512-channel universe caps out near 44 Hz no matter how fast the controller is, which is why large rigs are split across multiple DMX universes.
- Grand master — a real console's master fader scales every fixture's output together without touching the individual channel bytes stored per-fixture — drag it down and the whole rig dims in proportion.
- Haze density — beams are invisible in clean air; a theatrical haze machine seeds the air with fine particulate so the beam itself scatters light toward the audience. Zero haze makes the beams nearly invisible even at full intensity — only the floor wash shows.
- Drag the stage — drag left/right on the stage view to rotate it between a bird's-eye plan view and a proscenium (audience) view, the same range a lighting designer moves through when checking a plot from the front-of-house position.
- Run chase — automates the channel values over time, the same way a lighting console's chase/cue engine streams changing DMX data rather than a fixed snapshot.
- Channel histogram — the strip below the stage plots every active channel's live byte value (0–255), the same per-channel view a DMX analyzer or console channel-check screen shows.
Real-world relevance: this is the exact addressing and timing model used by every DMX512 lighting desk, from a single-scene budget controller to a full moving-light rig — the protocol hasn't changed since USITT standardized it in 1986.