Protocols used in Lighting Industry

BACnet

BACnet®, short for “Building Automation Control Network”, is a data communication protocol for building automation and control networks. BACnet is both an international (ISO) and ANSI standard for interoperability between cooperating building automation devices.
Originally developed in 1987 under the auspices of the American Society of Heating Refrigerating and Airconditioning Engineers (ASHRAE), BACnet has been an ANSI standard since 1995 and an ISO standard since 2003. BACnet is a registered trademark of ASHRAE.
BACnet is a standard data communication protocol that enables interoperability between different building systems and devices in building automation and control applications.
BACnet offers a flexible range of networking options including the use of Ethernet or IP-centric infrastructure and a simple, low cost twisted pair communication called MS/TP that is based on EIA- 485. A sophisticated routing capability allows scaling of BACnet internetworks into large and efficient systems, all within the same unified standard. BACnet uses an object-oriented model for abstracting and representing information. BACnet includes 54 standard objects that cover many common and generally useful applications. In addition, there is a mechanism for implementers to create and use their own non-standard objects that can be easily interoperable with other devices that choose to use them. This extensibility is free and guaranteed to be safe against unintended interference from other devices’ proprietary extensions. The object-based model has been proven to be both robust and reliable.


LONWorks

(local operating network) is a networking platform specifically created to address the needs of control applications. The platform is built on a protocol created byEchelon Corporation for networking devices over media such as twisted pair, powerlines, fiber optics, and RF. It is used for the automation of various functions within buildings such as lighting and HVAC; see building automation.
The protocol is also one of several data link/physical layers of the BACnet ASHRAE/ANSI standard for building automation.
Two physical-layer signaling technologies, twisted pair "free topology" and power line carrier, are typically included in each of the standards created around the LonWorks technology. The two-wire layer operates at 78 kbit/s using differential Manchester encoding, while the power line achieves either 5.4 or 3.6 kbit/s, depending on frequency.[2]
Additionally, the LonWorks platform uses an affiliated Internet protocol (IP) tunneling standard—ISO/IEC 14908-4[3] (ANSI/CEA-852[4]) -- in use by a number of manufacturers[5]to connect the devices on previously deployed and new LonWorks platform-based networks to IP-aware applications or remote network-management tools. Many LonWorks platform-based control applications are being implemented with some sort of IP integration, either at the UI/application level or in the controls infrastructure. This is accomplished with Web services or IP-routing products available in the market.
An Echelon Corporation-designed IC consisting of several 8-bit processors, the "Neuron chip" was initially the only way to implement a LonTalk protocol node and is used in the large majority of LonWorks platform-based hardware. Since 1999, the protocol has been available for general-purpose processors: A port of the ANSI/CEA-709.1 standard to IP-based or 32-bit chips.

DALI

DALI is a dedicated protocol for lighting control. A DALI system can be made up of control gear, control devices and bus power supplies.
In addition to the above, a DALI system also includes the bus wires that are used to connect together the DALI terminals of the various devices in the system.
Modern lighting technology requires systems that are flexible, simple and that provide room-based lighting control with just a few lowcost components. Its wiring needs to be easy, minimum combined with user-friendly operation.
One of the benefits of DALI is the flexibility in the way that devices may be addressed.
At the simplest level, all devices are addressed simultaneously by broadcast commands. This can allow control of lighting in a similar manner to 1-10V analogue control, without requiring any configuration of the individual devices. If a level (Direct Arc Power Command) is broadcast, then all control gear will act upon that command, changing their output to the same new level.
With simple configuration, DALI devices can be given one of 64 short-addresses. This allows individual control, configuration and querying of any single device in the system.
DALI devices can also be group addressed. For example, a DALI LED driver could be programmed to be in any combination of the 16 available groups. When a command is sent to a group, only devices that are in that group will be addressed. As thestandard expands to include control devices, further addressing methods will be allowed.
ZigBee
Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios.
The technology defined by the ZigBee specification is intended to be simpler and less expensive than other wireless personal area networks (WPANs), such as Bluetooth or Wi-Fi. Applications include wireless light switches, electrical meters with in-home-displays, traffic management systems, and other consumer and industrial equipment that requires short-range low-rate wireless data transfer.
Its low power consumption limits transmission distances to 10–100 meters line-of-sight, depending on power output and environmental characteristics.[1] ZigBee devices can transmit data over long distances by passing data through a mesh network of intermediate devices to reach more distant ones. ZigBee is typically used in low data rate applications that require long battery life and secure networking (ZigBee networks are secured by 128 bit symmetric encryption keys.) ZigBee has a defined rate of 250 kbit/s, best suited for intermittent data transmissions from a sensor or input device.
DMX

Technically, DMX is an abbreviation for DMX512-A, the ESTA (Entertainment Services Technology Association) Standard for controlling lighting equipment and related accessories. In January 2011 ESTA merged with PLASA, a similar organization in the UK. The new organization is called Plasa.
A wide variety of lighting control consoles, controllers and other devices that output DMX signals can be used to connect to an even greater variety of lighting fixtures and accessories that can be controlled by DMX.  DMX controlled lighting systems are used in many professional settings, including concert lighting, stage lighting, studio lighting, theme park attractions, and much more.
In recent years, the DMX standard is being used more frequently in Architectural lighting projects, including illumination of building exteriors, accent lighting, general purpose building management and high-end residential lighting.  This is due primarily to the high popularity of LED based lighting fixtures, which are frequently controlled via DMX signals.

A DMX512 network employs a multi-drop bus topology with nodes strung together in what is commonly called a daisy chain. A network consists of a single DMX512 controller – which is the master of the network — and one or more slave devices. For example, a lighting console is frequently employed as the controller for a network of slave devices such as dimmers, fog machines and intelligent lights.

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