Every LED driver spec sheet carries a dimming line — “0–10V,” “DALI,” “DMX,” “TRIAC/ELV,” or some combination. It reads like a minor compatibility detail, but it decides how the fixture wires, how it commissions, and whether it can ever join a networked control system. Pick the wrong protocol and you either strand a project on a dead-end control layer or pay for addressability nobody uses. Here’s how the four families actually differ.
0–10V: the analog default
0–10V is the workhorse of North American commercial lighting: two extra low-voltage control wires carry a DC signal where 10V is full output and 1V is minimum, with anything below 1V defined as the driver’s minimum level. Most commercial LED drivers follow IEC 60929 Annex E (“current sinking”): the driver sources the current, and the dimmer simply sinks it to pull the voltage down. That makes it cheap, robust over long runs, and easy to troubleshoot with a voltmeter.
The catches specifiers miss:
- It is polarity-sensitive. The purple (+) and pink or gray (–) control leads must land correctly. Reverse them and the signal collapses to roughly 0.7V — the fixture goes to minimum or off. Nothing is damaged, but a whole zone can read as “dead” from one flipped pair.
- There are two incompatible “0–10V” standards. IEC 60929 Annex E (lighting) and ESTA E1.3 (entertainment source-sourcing) are not interchangeable. Confirm which one a driver implements before mixing brands on a circuit.
- A dimmer controls a whole circuit, not a fixture. 0–10V has no addressing. Every driver on the pair dims together. Re-zoning means re-wiring.
- Minimum dim level is set by the driver, not the wall control. A driver rated to 10% will never reach 1% no matter what dimmer you pair it with. If a space needs deep dimming, that’s a driver-spec question — see our note on reading the dimming line against delivered lumens.
0–10V is the right call for straightforward zoned dimming in offices, warehouses, and linear runs where you don’t need per-fixture control.
DALI: addressable two-wire digital
DALI (Digital Addressable Lighting Interface), standardized as IEC 62386 with the DALI-2 certification program from the DALI Alliance, replaces the analog signal with a digital bus. A single two-wire line addresses up to 64 individual devices, each of which can be grouped, scened, and — critically — report status back.
What that buys you:
- Per-fixture addressing. Re-zoning is a software commissioning task, not a rewire. One physical bus can serve many logical groups.
- The bus is polarity-free. Unlike 0–10V, DALI’s two wires can land either way — fewer install errors on large jobs.
- Two-way communication. Drivers report lamp failure, energy use, and hours run — the foundation for daylight harvesting, occupancy response, and maintenance dashboards. The D4i extension standardizes the driver-level data that IoT and luminaire-level monitoring depend on.
The cost is commissioning. DALI needs addressing and programming — a labor line item and a specialized skill that 0–10V doesn’t. Specify it where the control intent is real: tunable-white offices, healthcare circadian schemes, and any project promising granular energy reporting or future flexibility. Don’t specify it to dim a stockroom.
DMX512: color, scenes, and big exterior shows
DMX512 (ANSI E1.11, “DMX512-A”) comes from stage and entertainment lighting and shows up on architectural and exterior product where color-changing RGBW and fast, synchronized scenes matter. One DMX universe carries 512 channels, letting a controller drive huge numbers of color and intensity parameters in lockstep.
It is a one-way, high-speed broadcast — no feedback, no addressing negotiation, and it expects proper data cabling and terminating resistors. That makes it overkill for static white dimming but ideal for façade and flood RGBW washes, bridges, signage, and any installation choreographed to music or time-of-day. Some premium exterior drivers accept both DMX and DALI so the same fixture can live in an entertainment or a building-controls world.
TRIAC and ELV: the line-voltage phase-cut family
TRIAC (leading-edge) and ELV (trailing-edge, sometimes “MLV/ELV”) dim by chopping the AC waveform on the line-voltage side — no separate control wires. They dominate residential and light-commercial retrofits because they reuse the existing switch leg and a familiar wall dimmer.
For commercial specification they carry real caveats: compatibility between a given driver and a given phase-cut dimmer is never guaranteed (flicker, buzz, drop-out, and limited low-end range are the classic symptoms), and there’s no addressing or feedback. Manufacturers publish tested dimmer compatibility lists for a reason — treat “TRIAC dimmable” as a claim to verify against that list, not a guarantee. Reserve phase-cut for small downlight or sconce counts where pulling control wire isn’t worth it.
A specifier’s decision shortcut
| Need | Protocol |
|---|---|
| Simple zoned dimming, low cost, long runs | 0–10V |
| Per-fixture control, tunable white, energy reporting, future flexibility | DALI / DALI-2 (D4i) |
| RGBW color, synchronized scenes, exterior shows | DMX512 |
| Retrofit on an existing switch leg, small counts | TRIAC / ELV (verify compatibility) |
What to actually check on the datasheet
- Which protocol, and to what depth? “0–10V dimming to 10%” and “0–10V dimming to 1%” are different products. The percentage is the spec that matters.
- The standard, not just the label. IEC 60929 Annex E vs ESTA E1.3 for 0–10V; DALI-2/D4i certification vs generic “DALI compatible.”
- Flicker. Deep dimming is where cheap drivers flicker. Look for a low-flicker or IEEE 1789-compliant claim if the space has cameras or sensitive occupants.
- Compatibility lists for anything phase-cut.
The dimming protocol is one of the few spec lines that constrains the entire control system downstream. Decide it early: match the protocol to the control intent — zoned, addressable, or color — and then hold the driver’s minimum dim level and flicker performance to the same scrutiny you give lumens and efficacy.