Lighting glossary

LED, DMX512, IP protection rating, color temperature… Short, accurate definitions of terms that come up often in facade lighting projects. Each term has its own link; you can share it directly when writing a specification or quote.

Accent lighting Accent lighting: Highlighting an element of a building, such as a column, arch, tower or entrance, by lighting it more brightly than its surroundings. It is usually done with narrow-beam spotlights.
Addressing Addressing: Assigning each luminaire or pixel on the control line a starting channel by which the controller recognizes it. In DMX512 the address is between 1 and 512; if addresses overlap, two luminaires receive the same command.
Art-Net DMX over Ethernet: A protocol that carries DMX512 data over an Ethernet network (UDP). Since a single network cable can carry many universes, it is used in large pixel projects; the device that converts data from the network into a DMX or SPI line is called a node.
Astronomical timer Astronomical timer: A timer that calculates the sunrise and sunset times for its location and switches the lighting on and off automatically every day. No manual adjustment is needed for the times that change with the seasons.

Beam angle Beam angle: The angle between the two directions in which a luminaire's luminous intensity falls to half its maximum value. A narrow angle carries light far, a wide angle spreads it over a nearby surface; in wall washer selection it is determined by the height of the wall.
Choosing a wall washer and lens angle
Binning LED binning: Sorting LEDs after production into bins by color coordinates, luminous flux and forward voltage. Using LEDs from the same bin in a project prevents differences in color and brightness between luminaires standing side by side.

Channel DMX channel: The control unit in DMX512 that carries a single value (0–255). A single-color luminaire uses 1 channel, an RGB pixel 3, an RGBW pixel 4.
Color rendering index CRI, Ra: A value (0–100) describing how accurately a light source shows colors compared with daylight. A high value is chosen for facades where the color of the material matters.
Color temperature and CRI
Color temperature CCT, Kelvin (K): A value describing how warm or cool white light appears. 2700–3000 K is perceived as warm, 4000 K as neutral, and 5000 K and above as cool white.
Color temperature and CRI
Connector Connector: A waterproof socket that connects luminaires to each other and to the power line in a pluggable way. At Motto, connectors are found on 24 V and 48 V DC luminaires; 220-240 V AC wall washers and in-ground luminaires are made without connectors, with a cable outlet only.
Controller Controller: A device or software that plays scenes and animations and generates a DMX512, Art-Net or SPI signal. With a calendar and an astronomical timer, it can start scenarios automatically.
What is a lighting control signal?

DALI Digital Addressable Lighting Interface: A two-way digital control protocol (IEC 62386) widely used in indoor lighting. Luminaires can be addressed and grouped and their status read; it is preferred for switching and dimming rather than fast color animations.
Decoder Decoder: A circuit that reads the DMX512 signal and drives the LED channels with PWM. In Motto's DMX luminaires the decoder is inside the luminaire; the luminaire takes the command at its own address from the line.
Dimmer Dimming: A circuit or device used to decrease and increase a luminaire's brightness. In LED luminaires, dimming is usually done with PWM or by lowering the driver's output current.
DMX512 Digital Multiplex: The most common digital control protocol in stage and architectural lighting. One line (universe) carries 512 channels, each taking a value from 0 to 255; the signal is transmitted over RS-485 to luminaires connected in series.
What is DMX512?
Driver LED driver: A power supply that converts mains voltage into the constant current or constant voltage (e.g. 24 V DC) an LED needs. A luminaire's lifetime and dimming quality depend largely on the driver.

Facade lighting Facade lighting: Lighting that designs how a building's exterior will look at night. Linear, wall washer, pixel and media mesh luminaires are used together to emphasize architectural lines, light a surface evenly or add colorful, dynamic scenarios to the facade.
How is a facade lighting project prepared?
Feedback Return feed: Connecting the power ends at the end of a luminaire run back to the power supply with a separate cable. Because the run is fed from both ends, voltage drop on long runs and the color and brightness differences seen in the luminaires at the end of the run are reduced.
Flicker Flicker: A fluctuation of light that is visible to the eye or appears as lines on camera. It is caused by low-frequency PWM or a poor-quality driver; it matters in projects where the facade is shared in photos and videos.

Glare Glare: An excessively bright source in the field of view causing discomfort or making it hard to see. On facades it is prevented by the luminaire's aiming, its optics and, if necessary, a shield.

IK protection rating IK code: A rating indicating the impact resistance of a luminaire housing (IEC 62262). It ranges from IK00 to IK10; IK10 means resistance to an impact energy of 20 joules.
IP and IK protection ratings
Illuminance Illuminance, lux (lx): The amount of light falling on a surface. Its unit is the lux: 1 lux is 1 lumen falling on one square meter. How bright a surface appears depends on the illuminance together with how much light the material reflects.
In-ground luminaire In-ground luminaire: A luminaire recessed into the ground that lights upward. Motto's in-ground luminaires work as recessed wall washers and wash the facade from its base.
In-ground luminaires
IP protection rating Ingress protection: A luminaire's level of protection against solid objects and water (IEC 60529). The first digit is for dust, the second for water: IP65 is fully dust-protected and resists water jets, IP67 can be temporarily immersed in water, and IP68 works continuously underwater under conditions specified by the manufacturer.
IP and IK protection ratings

LED Light Emitting Diode: A semiconductor that emits light when current passes through it. Thanks to its long life, high efficiency and suitability for color control, it is the basic light source used in facade lighting.
LED lifetime L70: The operating time after which an LED's luminous flux falls to 70% of its initial value. Lifetime is directly related to the LED's temperature, the current it is driven at and thermal management.
Light pollution Light pollution: Unnecessary or misdirected light disturbing the sky, surrounding buildings and living things. It is reduced with the right optics, luminaires aimed at the target and dimming during night hours.
Linear luminaire Linear luminaire: A luminaire with a long, slim housing that forms a continuous line when joined end to end. It accentuates edges, eaves, floor lines and window frames on the facade.
Linear facade luminaires
Luminaire Luminaire: A lighting unit that combines the light source (LED), optics, driver and housing. For facade luminaires, the housing's resistance to water, dust and impact is indicated by the IP and IK ratings.
Our products
Luminous efficacy Luminous efficacy, lm/W: The luminous flux a source produces for every watt it consumes. The higher the value, the less energy is needed for the same lighting.
Luminous flux Luminous flux, lumen (lm): The total amount of visible light a light source emits in all directions. Its unit is the lumen; it shows how much light a luminaire gives, not where the light goes.
Luminous intensity Luminous intensity, candela (cd): The amount of light a source sends in a particular direction. Its unit is the candela; in narrow-beam luminaires, the same luminous flux gives a higher luminous intensity.

MacAdam ellipse SDCM: A measure showing the threshold at which the human eye can distinguish the color difference between two white lights. The smaller the number of steps, the greater the color consistency; a difference of 3 SDCM or less is hard to see.
Media mesh screen Media facade, mesh LED: A transparent LED screen mounted on a facade, made of pixel strips arranged at intervals. It shows imagery, text and animation without covering the building; the view out and airflow continue.
Media mesh screen systems
Media server Media server: A device or software that distributes video and animation content to pixels according to the luminaires' layout on the facade and sends it as Art-Net, sACN or DMX.

Optics Lens, reflector: A lens or reflector that gathers the LED's light into the desired beam angle. The same luminaire can light a narrow column or a wide wall with different optics.

Pixel Pixel: The smallest unit of light whose color and brightness can be controlled individually. A pixel can be a single LED or a group of LEDs controlled together.
Pixel mapping Pixel mapping: Distributing video or animation to pixels according to the real layout of the luminaires on the facade. This way, luminaires spread across a facade behave like a single screen.
Pixel pitch Pixel pitch: The distance between the centers of two neighboring pixels. The smaller the pitch, the sharper the image looks up close; a large pitch covers a wide surface with fewer pixels on facades viewed from afar.
Pixel-controlled luminaire Pixel-controlled luminaire: A luminaire that controls the color of each pixel in its housing individually. Animations that flow, ripple and form text on a facade are made with these luminaires.
Pixel-controlled linear luminaires
Point pixel luminaire Pixel dot: A pixel luminaire that lights from a single point and, placed on a facade in a grid, creates large-scale imagery and animation.
Pixel-controlled point luminaires
Power factor Power factor, PF: The ratio of the real power a driver draws from the mains to the apparent power. A power factor close to 1 shows that no unnecessary reactive current is drawn from the mains.
PWM Pulse width modulation: A method of adjusting an LED's brightness by switching the current on and off very quickly and changing the proportion of time it stays on. If the frequency is not high enough, flicker is visible on camera and to the eye.

RDM Remote Device Management: An extension protocol (ANSI E1.20) providing two-way communication over the DMX512 line. Addresses can be assigned to luminaires remotely, and temperature and fault information can be read.
RGB and RGBW Red, Green, Blue (White): Creating color by mixing red, green and blue LEDs. In RGBW, the added white LED gives a cleaner white and pastel tones.
What are RGB, RGBW, DW and MC?
RS-485 EIA-485: A serial communication standard that is the physical layer of DMX512, working with an inverted-phase signal over two wires. It is noise-resistant; twisted-pair cable is used on long runs.

sACN Streaming ACN, ANSI E1.31: A standard protocol that carries DMX data over a network. Like Art-Net, it transmits many universes over a single Ethernet network.
Scene Scene, cue: A lighting state or animation stored in the controller. Holiday, New Year or special-day scenes can be linked to a calendar and played automatically.
SPI Serial Peripheral Interface: A serial communication method that sends data to the LED driver ICs in pixel luminaires. It drives large numbers of pixels without being bound by DMX's 512-channel universe limit; Motto's VMesh media mesh screens run on SPI.
What is SPI pixel control?
Spotlight Spotlight: A narrow-beam luminaire with a small housing. It is used to highlight a single element such as a column, sculpture, logo or facade detail.
Spotlights

Termination Termination: Connecting a 120 Ω resistor to the data wires at the last device of a DMX512 line; it prevents the signal from reflecting back from the end of the line. In Motto's DMX wall washers and in-ground luminaires, termination is done inside the luminaire, and no separate resistor is fitted.
Thermal management Thermal management: Removing the heat produced by an LED through the housing and heat sink surfaces. As an LED heats up, its luminous flux falls and its lifetime shortens; that is why the aluminum housing is also a heat sink.
Transparency Transparency: The proportion of a surface that remains open in media mesh screens. As transparency increases, the view out from the building and wind passage increase, and the number of pixels on the same surface decreases.
Tunable white Tunable white: A luminaire whose color temperature can be adjusted from warm white to cool white. It is achieved by changing the ratio of two different white LEDs; the same facade can be shown in a warm tone in the evening and a cooler one at night.
What are RGB, RGBW, DW and MC?

Uniformity Uniformity: How evenly illuminance is distributed over a surface; usually expressed as the ratio of the minimum value to the average. To avoid a patchy or broken look on the facade, luminaire spacing and beam angle are chosen together.
Universe DMX universe: A 512-channel DMX512 line. Since an RGB pixel uses 3 channels and an RGBW pixel 4, one universe can drive at most 170 RGB or 128 RGBW pixels.

Voltage drop Voltage drop: The loss of voltage as current travels along cables and luminaire runs, due to conductor resistance. It is noticeable on low-voltage (24 V, 48 V DC) lines; luminaires at the end of the run may glow dimmer or in a different color. It is prevented with cable cross-section, run length and return feed.

Wall washer Wall washing luminaire: A linear luminaire that lights a wide surface evenly and continuously. It is placed at the base or top of the wall; spreading light along the surface, it shows the facade as a whole.
Wall washer luminaires