Choosing a control protocol in 2026

Control is where lighting schemes are most often compromised, usually because the protocol was chosen by the electrical contractor on price rather than by the designer on intent.

The field, briefly

0–10 V / 1–10 V. Analogue. A low-voltage pair carries a dimming level to a whole circuit. Cheap, universal, and understood by every electrician on earth. Not addressable — the circuit is the smallest unit of control. Polarity-sensitive, susceptible to voltage drop on long runs, and gives you no feedback whatsoever. Legitimate for simple, static installations with few zones.

DALI-2. Digital, addressable, bidirectional. Up to 64 addresses per bus, 16 groups, 16 scenes. Every fitting is individually reachable and reports its own status and faults. DALI-2 (unlike the original DALI) certifies control devices as well as gear, so certified parts genuinely interoperate. This is the default for commercial architectural work and should be your starting assumption.

D4i. DALI-2 plus a defined data model inside the luminaire — energy metering, diagnostics, lifetime and temperature data — and a bus supply for a sensor mounted on the fitting. The foundation for luminaire-level analytics and for connected outdoor lighting.

DALI+. DALI messaging carried over IP and wireless (Thread) rather than the two-wire bus. Lets a wireless retrofit zone share one commissioning model and one control language with the wired new-build parts of the same estate. Actively maturing through 2026, with wireless-to-DALI gateways now common at the fair stands.

DMX512 / RDM. From stage lighting. 512 unidirectional channels per universe, high refresh rate, built for smooth colour and movement. The standard choice for colour-changing façades, media walls and any pixel work. RDM adds a return path for addressing and status.

Matter. IP-based application layer over Wi-Fi and Thread, aimed at consumer interoperability. Increasingly present where residential and hospitality lighting meets the wider smart-building stack. It is not a replacement for DALI or DMX in architectural work — it lacks the addressability granularity and scene fidelity — but it is a real integration layer at the boundary.

Three questions that decide it

1. Do you need to address the individual fitting? If a single luminaire ever needs a different level or colour from its neighbour on the same circuit, you need addressability. That rules out 0–10 V immediately. In practice this is true of almost every scheme with any design ambition.

2. Do you need smooth colour at high refresh? Colour-changing façades, media content, anything with movement: DMX. DALI can change colour (device type 8) but its refresh rate makes fades visibly steppy on large fields.

3. Do you need the installation to report back? Energy sub-metering, lamp-failure alerts, hours-run for maintenance planning: DALI-2, and D4i if you want data at the luminaire rather than the driver.

A very common and entirely correct answer on a mixed project: DALI-2 for the interior, DMX for the façade, a gateway between them, and one front end.

The parts everyone underestimates

Commissioning is a work package, not a switch. It needs a named party, a fee line, a defined scene schedule agreed with the client, site attendance and a written record. Uncommissioned DALI is more expensive and less capable than 0–10 V. Every scheme that “never worked properly” failed here.

Write the scene schedule during design. Room by room: scene name, which groups, what level, what CCT, what fade time, what triggers it. It is a table you can produce in detailed design and it is the single most valuable document you will hand the commissioning engineer.

Bus topology and load. DALI is 64 addresses, 250 mA typical bus supply, 300 m maximum cable run. Fittings with multiple channels (tunable white, RGBW) consume multiple addresses — a tunable white fitting is commonly two. Count addresses at the schedule stage, not on site.

Emergency lighting is a parallel system. Self-test emergency gear can sit on DALI, but the emergency function must remain independent of the control system’s health. Coordinate it early with the fire strategy; retrofitting this is painful.

“DALI compatible” ≠ DALI-2 certified. Only certified products carry an interoperability guarantee. Ask for the certificate number, and check it on the DALI Alliance register.

Cybersecurity is now in scope

IES LP-6-25 added guidance on cybersecurity for lighting controls, which tells you where the industry has arrived. Once lighting sits on the building IP network, it becomes an attack surface and an IT stakeholder appears.

Practical minimum: put lighting on its own VLAN, change default credentials at commissioning and record that you did, establish who owns firmware updates for the lifetime of the installation, and get the IT team into a coordination meeting before the gateway is specified rather than after their security review blocks handover.

Rules of thumb

• Simple, static, few zones, tight budget → 0–10 V, and be honest with the client about what they are giving up.
• Any commercial project with design intent → DALI-2, D4i where luminaire data has value.
• Colour, movement, pixels, façade → DMX/RDM.
• Wireless retrofit inside a wired estate → DALI+ with gateways.
• Residential and hospitality touching a wider smart-home stack → DALI or DMX at the core, Matter at the boundary.

And whatever you choose: budget the commissioning, write the scene schedule, and name the person who owns the system in year three.