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- 0-10V dimming
- An analog control method in which a low-voltage signal between 0 and 10 volts sets a driver's light output. It is one-way, so the driver can't report status, and turning a fixture fully off usually needs a relay on the line-voltage side.
A
- AHJ (authority having jurisdiction)
- The office or official that enforces codes on a project, such as a city or county building department or a state fire marshal. Energy-code adoption varies across Mississippi, Tennessee and Alabama, so we confirm the applicable edition with the AHJ on every project.
- ANSI/IES RP-46-25
- The Illuminating Engineering Society's recommended practice for daytime interior lighting that accounts for non-visual effects such as circadian response. It is a design reference, not a code requirement.
- ASHRAE 223P
- A proposed ASHRAE standard for semantic models of building systems, describing how equipment, sensors and spaces connect. It draws on Brick and Project Haystack; check its current publication status before writing it into a specification.
- ASHRAE 90.1
- ASHRAE's energy standard for commercial buildings, which sets lighting power limits and required controls. DOE determined that 90.1-2022 saves roughly 10% over 90.1-2019; which edition applies to your project depends on local adoption.
- Astronomical time clock
- A time clock that calculates sunrise and sunset for its location and date, so exterior lighting follows the seasons without manual adjustment. It needs correct coordinates, time zone and daylight-saving settings.
- Automatic receptacle control
- Controls that switch off designated outlets when a space is unoccupied or after hours. Recent energy codes require them in some spaces, and the 2024 IECC adds functional testing for them.
B
- BACnet
- ASHRAE Standard 135, the most widely used open protocol for building automation. It defines objects, such as binary values and analog inputs, and services that let lighting, HVAC and metering systems from different manufacturers exchange data.
- BACnet/IP
- BACnet carried over IP networks using UDP, on port 47808 by default. It relies on broadcasts for device discovery, which is why networks that span subnets need a BBMD.
- BACnet/SC
- BACnet Secure Connect, defined in ASHRAE 135 Annex AB. It carries BACnet over TLS-secured WebSockets with certificate-based mutual authentication through a hub, and it doesn't need BBMDs.
- BBMD (BACnet Broadcast Management Device)
- A BACnet/IP device that forwards broadcast messages between IP subnets so devices on different subnets can find each other. Misconfigured BBMDs are a common cause of broadcast storms and missing devices.
- Bluetooth Mesh NLC profiles
- Bluetooth SIG profiles that standardize networked lighting control functions such as occupancy sensing, ambient light sensing, dimming, energy monitoring and HVAC integration on Bluetooth Mesh. Products qualified to the same profile are designed to work together across manufacturers.
- BMS (building management system)
- The central control system for HVAC and often other building systems, also called a BAS. Lighting connects to it to share occupancy, status and energy data.
- Brick Schema
- An open semantic model that describes building equipment, points and spaces and the relationships between them. It lets software find, for example, every occupancy sensor serving a given VAV box without hand-mapping point names.
C
- C137.9 (ANSI/NEMA C137.9)
- A standard format for lighting control system configuration reports, recording as-commissioned settings in a consistent structure across manufacturers. DLC NLC 5.2 references it, and we ask for it in specifications where the platform supports it.
- CCT (correlated color temperature)
- A measure of how warm or cool white light looks, expressed in kelvins. Lower values, around 2700 K, look warm; higher values, 5000 K and above, look cool.
- COMcheck
- Software from the US Department of Energy used to show that a commercial building's envelope, lighting and mechanical design complies with the IECC or ASHRAE 90.1. Many jurisdictions accept its reports with permit submissions.
- Commissioning
- Verifying that a system is installed, configured and performing according to the owner's design intent, documented through functional testing. For lighting controls, it goes beyond manufacturer startup to test every sequence in the building.
- Configuration report
- A record of every setting in a commissioned controls system: zones, groups, sensor timeouts, trim levels, schedules and network addresses. It lets the next technician restore or change the system without guessing.
- CRI (color rendering index)
- A measure, up to 100, of how accurately a light source renders colors compared with a reference source. Tasks such as fabric matching and clinical assessment call for high values, typically 90 or above.
D
- D4i
- A DALI Alliance certification for DALI inside the luminaire that makes key features mandatory: auxiliary power for sensors and network nodes, and stored luminaire, energy and diagnostic data. It builds on DALI-2.
- DALI-2
- The second generation of the Digital Addressable Lighting Interface (IEC 62386), with product certification by the DALI Alliance. It is a two-wire, bidirectional bus supporting up to 64 control gear per bus, plus input devices such as sensors and keypads.
- Daylight harvesting
- Automatically dimming electric lighting in response to available daylight, measured by photosensors, to hold a target light level. Savings depend on the size of the daylit zone and how well the sensors are calibrated.
- Daylight zone
- The floor area near windows or under skylights that receives enough daylight to dim electric lighting. Energy codes define its size and, above set thresholds, require the luminaires in it to be controlled separately.
- Demand charge
- The part of a commercial electric bill based on the highest power draw (kW) in a billing period rather than total energy (kWh). High-end trim and demand response can lower it; estimates that count only kWh miss it.
- Demand response (DR)
- Reducing or shifting electrical load when a utility or grid operator signals, usually during peak periods. Lighting is a useful DR resource because it can dim quickly and by a predictable amount.
- Dim-to-off
- A driver's ability to go from its lowest dimming level to fully off on a control signal alone. Without it, a separate relay has to disconnect power to the fixture.
- Dimming curve
- The relationship between a control signal and light output. Logarithmic and square-law curves match how the eye perceives brightness better than linear ones, which matters most at low levels.
- DLC (DesignLights Consortium)
- A nonprofit that sets technical requirements for LED products and networked lighting controls and publishes the Qualified Products List. DLC estimates average savings of about 49% for NLC and 63% for NLC with LLLC.
- DLC NLC5 / NLC 5.2
- The DesignLights Consortium's technical requirements for networked lighting control systems. Version 5.2 adds HVAC integration and configuration reports in ANSI/NEMA C137.9 format, and cybersecurity requirements have applied since NLC5.
- Driver
- The electronic power supply inside an LED luminaire that converts line voltage into the current the LEDs need. Its control interface, such as 0-10V, DALI-2, D4i or a wireless node, decides how the fixture can be dimmed and monitored.
- Dual-technology sensor
- An occupancy sensor that combines passive infrared with ultrasonic or microwave detection. Requiring both to turn lights on, but either to keep them on, reduces false triggers and false offs.
E
- EM&V (evaluation, measurement and verification)
- The process utility programs and regulators use to determine how much energy a program actually saved. It typically includes sampling, metering and engineering review across many projects.
- Emergency lighting (UL 924)
- Egress lighting that must operate during a power failure. Controlled emergency fixtures use UL 924 listed devices that force them to full output when normal power is lost, whatever the control system is doing.
- ENERGY STAR Portfolio Manager
- The EPA's free online tool for tracking a building's energy and water use and benchmarking it against similar buildings. Some jurisdictions and programs require benchmarking through it.
F
- Firmware
- The software that runs inside sensors, drivers, gateways and switches. Updates fix bugs and security issues, so specifications should state who applies them, how often, and for how many years the manufacturer will provide them.
- Flicker
- Rapid variation in light output, visible or not, often caused by driver design at low dimming levels. It can cause discomfort, and stroboscopic effects near rotating or reciprocating machinery.
- Functional testing
- Running each control sequence through its states, such as occupied, vacant, daylight, schedule and override, and recording the results. The 2024 IECC (section C408.3) requires functional testing of lighting controls.
G
- Gateway
- A device that connects a lighting control network to another network, such as the building's IP network, the BMS or a cloud service. It is often where protocols are translated and where security reviews focus.
- Grid-interactive efficient building (GEB)
- A building that is efficient, connected and able to shift or reduce load in response to grid signals. Lighting controls with demand response and OpenADR support are one of its building blocks.
H
- High-end trim
- Setting the maximum output of a fixture or zone below 100% at commissioning, to match what the space needs. The 2024 IECC requires functional testing of high-end trim where it is installed.
- Hold time (time delay)
- How long an occupancy or vacancy sensor waits after the last detected motion before dimming or turning off lights. Too short causes complaints; too long wastes energy.
- Human-centric lighting
- Lighting designed for the visual, emotional and biological effects of light on people, often using tunable white and daylight. Benefits depend on design and dose, so be wary of products that promise health outcomes.
I
- IEC 62443
- A series of international standards for securing industrial automation and control systems, covering both system operators and component suppliers. Part 4-2 sets technical security requirements for components such as controllers and gateways.
- IECC (International Energy Conservation Code)
- The International Code Council's model energy code. The 2024 edition lowers the threshold for daylight-responsive controls and requires functional testing of high-end trim and demand-responsive controls where installed; adoption varies by state and locality.
- Illuminance
- The amount of light falling on a surface, measured in foot-candles in the US or lux internationally; one foot-candle is about 10.76 lux. It is what a light meter reads and what trim targets are set against.
- IPMVP
- The International Performance Measurement and Verification Protocol, published by the Efficiency Valuation Organization. It defines four options, A to D, for measuring savings, from isolating a single retrofit to modeling a whole facility.
L
- Lighting-as-a-Service (LaaS)
- A contract in which a provider installs and maintains lighting and controls for a recurring fee instead of a purchase. Whether it counts as a lease under ASC 842 depends on the contract terms, so ask your accountant.
- LLLC (luminaire-level lighting control)
- A networked control approach in which every luminaire has its own integrated occupancy and ambient light sensors and can be configured individually. DLC estimates average savings of about 63% for NLC with LLLC.
- Load shed
- A deliberate, temporary reduction in electrical load, such as dimming lights by a set percentage, in response to a demand response event or price signal.
- LPD (lighting power density)
- Installed lighting power divided by floor area, in watts per square foot. Energy codes cap it by building or space type.
- Lumen maintenance
- How much of its initial light output a source keeps over time, often stated as L70, the hours until output falls to 70%. Some controls start fixtures trimmed and raise output as they age to hold a constant level.
M
- M&V (measurement and verification)
- Measuring the energy savings of a specific project by comparing actual use against an adjusted baseline. It is how an owner, lender or incentive program confirms that projected savings happened.
- Matter
- A Connectivity Standards Alliance application standard for interoperable smart devices that runs over Thread, Wi-Fi and Ethernet. The CSA now lists commercial buildings as a target market, but there are no commercial lighting device profiles yet.
- Melanopic EDI
- Melanopic equivalent daylight (D65) illuminance, defined in CIE S 026 and measured in lux. It estimates how strongly light stimulates the retinal cells involved in circadian response, and it is the usual metric in non-visual lighting design.
- Modbus
- A simple register-based protocol from industrial control, used over serial lines (RTU) or TCP/IP. It is common on meters, drives and inverters, but carries no built-in meaning or security, so each register has to be mapped by hand.
- MQTT
- A lightweight publish-subscribe messaging protocol in which devices send data to a broker and applications subscribe to topics. It is widely used for IoT telemetry and is one of the ways Lytbit Ledger exports data.
N
- Networked lighting controls (NLC)
- A system of individually addressable luminaires, sensors and controllers that communicate over a network to provide zoning, occupancy, daylight, trim and scheduling. DLC estimates average savings of about 49% for NLC.
O
- Occupancy analytics
- Using sensor data to measure how often and how intensively spaces are used, by room, floor or zone. It informs real-estate, cleaning and HVAC decisions, and should be designed for privacy from the start.
- Occupancy sensor
- A sensor that turns lights on automatically when it detects people, and off or down after a hold time. Common technologies are passive infrared, ultrasonic, microwave and combinations of them.
- OpenADR
- Open Automated Demand Response, an open standard for sending demand response and price signals from utilities or aggregators to buildings. OpenADR 3.0 uses a REST-style API that is simpler to implement than earlier versions.
P
- Partial-off control
- A sequence that drops lighting to a reduced level, rather than off, when a space is vacant. It suits corridors, stairwells and warehouse aisles, where full darkness would be unsafe or unwelcome.
- Passive infrared (PIR)
- A sensing technology that detects warm bodies moving across zones in the sensor's field of view. It needs line of sight and is less sensitive to small movements than ultrasonic sensing.
- Photosensor
- A sensor that measures light, used for daylight harvesting indoors and dusk-to-dawn switching outdoors. Indoor photosensors need calibration after installation to hold the right target.
- PoE (Power over Ethernet)
- Delivering DC power and data over the same Ethernet cable. IEEE 802.3bt allows up to 90 W per port at the source, enough for many LED luminaires, within a 100 m cable channel.
- Points list
- The list of data points, such as occupancy states, light levels and energy readings, that one system will share with another, with names, units and object types. Agreeing on it early is the cheapest part of any integration.
- Project Haystack
- An open-source initiative that defines tags and a data model for building and equipment data, so software can find and interpret points such as zone occupancy. Recent versions add a more formal ontology, and the Haystack and Brick communities have worked toward alignment.
Q
- QPL (Qualified Products List)
- The DesignLights Consortium's public list of products that meet its technical requirements. Many utility programs require a fixture or control system to appear on the QPL before it qualifies for an incentive.
R
- Re-commissioning
- Repeating functional testing and adjustment on a system that was commissioned before, to correct drift from changed layouts, replaced devices and permanent overrides. It is often the lowest-cost energy measure in an existing building.
S
- Scene
- A saved combination of light levels, and with tunable white also color temperatures, for a group of fixtures, recalled with one button or command. Typical examples are Presentation, Cleaning and Night.
- Sequence of operations
- The written description of how a control system should behave in each space and condition: what turns on, when, to what level and for how long. It is the document every functional test is measured against.
- Sparkplug
- An open specification on top of MQTT that defines topic names, payload encoding and device state messages, so data arrives consistent and self-describing. Sparkplug 3.0 is published as ISO/IEC 20237:2023.
- Sweep
- A scheduled command that turns lights off or down across a building or area, typically after hours, while letting occupants override locally. It catches lights left on in spaces without sensors.
T
- Task tuning
- Adjusting each area's light level to the work done there, usually after observing the space in use. In practice it is carried out through high-end trim settings, zone by zone.
- Thread
- An IPv6-based, low-power wireless mesh network built on IEEE 802.15.4. It is the main low-power transport for Matter devices.
- Title 24
- California's building energy efficiency standards. The 2025 edition, effective January 1, 2026, requires continuous dimming to 10% or lower, occupancy sensor delays of 20 minutes or less, and daylighting controls at 75 W or more, which matters to owners with California sites.
- Tunable white
- Luminaires whose color temperature can be adjusted, usually by mixing warm and cool LED channels. They are typically controlled over DALI-2 (device type 8) or two 0-10V channels.
- TVA EnergyRight
- The Tennessee Valley Authority's energy efficiency program, offered through local power companies such as Tupelo Water & Light and MLGW. Commercial lighting incentives require pre-approval before work starts, and networked controls receive extra credit.
V
- Vacancy sensor
- A sensor that turns lights off automatically when a space empties but requires someone to turn them on by hand. It saves more than auto-on sensing because lights stay off when daylight or spill light from a corridor is enough.
- VLAN (virtual LAN)
- A logical network segment on shared switches, used to separate lighting and building system traffic from office IT traffic. Segmentation limits what a compromised device can reach.
Z
- Zhaga-D4i
- A certification that combines a standardized Zhaga connector on the luminaire housing with D4i driver features, so sensors and network nodes plug in without tools. It is most common on outdoor and area luminaires.
- Zigbee
- A low-power wireless mesh protocol on IEEE 802.15.4, maintained by the Connectivity Standards Alliance. Zigbee 4.0, announced in late 2025, updates the specification and adds Suzi, a sub-GHz option for longer range.
- Zone
- A group of luminaires controlled together by one sensor, switch or schedule. With luminaire-level control, zones are defined in software and can change without rewiring.
