Lighting controls

The short answer

If the lighting only needs to come on at dusk and go off later, a photocell and timer is all you need. If you want dimming, groups or white scenes, use DALI. If you want colour change, moving effects or many individually controlled zones, use DMX512, or an SPI pixel controller for some flexible LED. Whatever you choose, plan a curfew: switch off or dim when the building no longer needs to be seen.

Control options vary by product. Each product page lists what’s available, and we confirm the driver and control for every line of your schedule.

The options at a glance

Control	What it does	Wiring	Typical use
On/off with photocell and timer	Switches on at dusk, off at a set time	Mains, switched by a photocell, time switch or contactor	Simple white schemes, signs, small buildings
DALI / DALI-2	Digital dimming, grouping and scenes, with status feedback	Mains + 2-core DALI bus	White and tunable white schemes, buildings with a lighting control system or BMS
DMX512 / RDM	Fast control of many channels for colour and effects	Low-voltage data cable, daisy-chained	RGB, RGBW and pixel schemes, events, landmarks
1–10 V	Analogue dimming signal	Mains + 2-core control	Existing analogue systems
SPI pixel	Individually addressable pixels on flexible LED	Data line run with the low-voltage supply	Effects and animations on strip and neon

Photocells, timers and curfews

A photocell switches lights on when it gets dark, so you don’t have to adjust times through the year. Pair it with a time switch or astronomical clock to switch off or dim at a set hour. Mount it where it sees the sky but not the lighting it controls.

A curfew is the time after which lighting is switched off or reduced. The ILP Guidance Note GN01 sets tighter obtrusive light limits after curfew, and planning conditions often specify one. A curfew also cuts running costs.

DALI and DALI-2

DALI (Digital Addressable Lighting Interface) is defined in IEC 62386. Each driver has its own address, so luminaires can be grouped, dimmed and set to scenes individually, and report faults back to the system. A single DALI line supports up to 64 control gear addresses, 16 groups and 16 scenes. DALI-2 is the current certified version, with better interoperability between drivers, sensors and controllers from different manufacturers. Colour control is covered by a separate part of the standard (device type 8), used for tunable white and some colour luminaires.

Choose DALI for white or tunable white facades where you need dimming and scenes, especially if the building already has a DALI system. It’s less suited to fast colour effects.

DMX512 and RDM

DMX512 is defined in ANSI E1.11. One DMX line, called a universe, carries 512 channels. Each controllable part of a luminaire uses one or more channels: a single-colour dimmer uses one, an RGB zone three and an RGBW zone four. So one universe can drive, for example, 128 RGBW zones (512 ÷ 4). Larger schemes use several universes, often carried over a network using protocols such as Art-Net or sACN (ANSI E1.31).

RDM (Remote Device Management, ANSI E1.20) adds two-way communication over the same cable, so addresses can be set and faults reported remotely. That’s very useful when luminaires are high on a building.

Practical points for DMX: use cable designed for data (RS-485, 120 Ω), daisy-chain luminaires rather than branching the cable, fit a terminator at the end of each line, and use splitters where a line serves many devices or needs to branch.

1–10 V

1–10 V is an older analogue dimming method, in which a control voltage between 1 and 10 V sets the light level. It’s simple, but has no addressing or feedback, so we’d normally suggest DALI for new installations.

SPI pixel control for flexible LED

Some flexible LED and neon comes in pixel versions, with a built-in chip controlling each short section. These use an SPI (serial peripheral interface) data signal from a pixel controller, which can often take DMX or network input from a wider control system. SPI isn’t a single standard: the controller must support the chip type used in the strip, and the data cable between controller and first pixel has a limited length. Check both with us before you design the layout.

Constant voltage and constant current strip

Type	How it works	Points to note
Constant voltage (CV), usually 24 V DC	Powered by a fixed-voltage supply; the strip regulates current along its length	Easy to cut to length at marked points and flexible to design with, but brightness can fall along long runs because of voltage drop
Constant current (CC)	Each section regulates its own current	More even brightness over longer runs, but cutting rules and supply options are specific to the product

Voltage drop and maximum run lengths

On a low-voltage strip, the copper inside the strip and the cables feeding it have resistance, so voltage falls along the run. Too much drop shows as dimmer light, or a colour shift, at the far end.

To keep runs even:

• Keep within the product’s maximum run length from a single feed point. This is stated for each flexible product.
• Feed long runs from both ends, or from the middle, or add further feed points along the run.
• Size the feed cable for the current and distance. Current is power divided by voltage: for example, a 10 m run at 10 W per metre is 100 W, which at 24 V is about 4.2 A. Longer cables need a larger cross-section to keep the drop acceptable.
• Put power supplies close to the strip where you can, in a ventilated, accessible and suitably rated enclosure.
• Allow headroom rather than loading power supplies to their full rating.

Scenes and curfews in practice

A typical scheme comes on at dusk, drops to a reduced level once streets are quieter, and switches off or to a low security level at curfew, with special scenes for events programmed in advance. Agree the scenes, times and who can change them before commissioning, and leave the written settings with the client.

How we can help

We can suggest a control approach, prepare control schematics and confirm the right driver or controller for each product. Start a project.

Sources: IEC 62386, Digital addressable lighting interface; ANSI E1.11, USITT DMX512-A; ANSI E1.20, Remote Device Management over DMX512 networks; ANSI E1.31, Streaming ACN; Institution of Lighting Professionals, Guidance Note GN01, The Reduction of Obtrusive Light.