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Digital Addressable Lighting Interface (DALI) is a technical standard for network-based systems that control lighting in buildings. It is an open standard alternative to Digital Signal Interface (DSI), on which it is based. The DALI standard, which is specified in the IEC 60929 standard for fluorescent lamp ballasts, encompasses the communications protocol and electrical interface for lighting control networks.


Protocol description
2 Wire Bus, Power from DALI Control
• Half Duplex Comms via 1 wire DALI Data line
• Max of 63 addressable devices on 1 DALI bus.

Baud Rate = 1200 bits/sec.

Hardware platform
• Modified UART based 1200 with Bi-phase Decode/Encode. + programmable STOP/START bits.
• Interrupt on Receive and Transmit of Data.
• Optical isolation required.


• Light Ballast



Daylighting is the practice of placing windows, skylights or other transparent media, and reflective surfaces so that, during the day, natural light provides effective internal lighting.


Within the overall architectural design of a building, particular attention is given to daylighting when the aim is to maximize visual comfort, productivity, or to reduce energy use. Energy savings from daylighting are achieved in two ways:


reduced use of electric lighting or

from passive solar heating or cooling


Electric lighting energy savings can accrue because occupants choose not to switch their lights on, or because an automatic lighting control system ("photocontrol system") switches the lights off or dims them to a lower level.


Demand Limiting

Demand Limiting (or Load Shedding or Demand Response) predicts potential energy peaks by monitoring the building’s utility meters, then employing a flexible control strategy to defer energy-consuming loads to times of the day when energy usage is billed at lower rates. Load Rolling reduces total energy usage by temporarily turning off or resetting noncritical equipment.


Demand Response

See Demand Limiting


Digital Addressable Lighting Interface (DALI)

A digital protocol for the controlling of lighting in buildings that addresses electrical ballasts.

DALI was established as an open standard rival to Digital Signal Interface (DSI), on which it is based. DALI is standardized in accordance with International Electrotechnical Commission IEC 60929, standard for fluorescent lamp ballasts.

Each piece of operating equipment with a DALI interface can be communicated with over DALI individually. Using a bi-directional data exchange, a DALI controller can query and set the status of each light. As a standalone system, DALI can be operated with a maximum of 64 devices. Alternatively, DALI can be used as a subsystem via DALI gateways.


DALI Action Group


Damp Location

UL listing for fixtures used in a moist unexposed area, such as a bathroom or porch area.


Design Energy Cost

(as relates to ASHREA/IESNA standard 90.1 and LEED) The Design Energy Cost is calcualted by a simulation program based on the proposed design of the building in its final form, that is, the design submitted for the building permit approval. Compare this to Energy Cost Budget. Design Energy Cost refers to the design case of the project. Energy Cost Budget refers to the baseline case of the project as defined by a standard such as ASHRAE 90.1 (reference: ASHRAE Std. 90.1 Users Manual)



Control that varies the output of the light source by reducing the voltage or current to the lamp.


Direct Digital Control (DDC)

A control system in which a digital computer or microprocessor is directly connected to the valves, dampers, and other actuators which control the system, as opposed to indirectly controlling a system by resetting setpoints on an analog pneumatic or electronic controller.


Direct Lighting

Lighting that casts all, or at least 90%, of its light downward. The term can also refer to the distribution of light or the fixtures that produce this type of lighting. With intense beams, direct lighting is very dramatic, rendering forms and textures well. Typical fixtures include recessed lights, track lights, some pendant lights and task lights.


Direct-Indirect Lighting

Light comes from up and down. This light is well balanced and pleasing. Light that is predominately direct is also called”semi-direct.” Typical fixtures include most pendant lights, wall brackets and wall valances. Uses include task/ambient lighting over tables and in hallways.


US DOEDOE - U.S. Department of Energy

United States Department of Energy (DOE) is Cabinet-level department of the United States government responsible for US energy policy and nuclear safety.


U.S. Department of Energy
c/o Superintendent of Documents
U.S. Government Printing Office
Washington, DC 20402-9325



A logical collection of devices on one or more channels. Communications can only take place among devices configured in the same domain.



Acronym for Dynamic Data Exchange. A standard Microsoft Windows protocol that defines a mechanism for Windows applications to share
information with one another.

When applications share information with each other using DDE, they are said to be holding a DDE conversation. Each conversation has a well-defined beginning, middle, and end. To begin a conversation, one application, known as the client or destination application asks another application, known as the server or source application to open a communications channel.