LonWorks is a networking platform specifically created to address the unique performance, reliability, installation, and maintenance needs of control applications. The platform is built on a low bandwidth protocol created by Echelon Corporation for networking devices over media such as twisted pair, powerlines, fiber optics, and RF. It is popular for the automation of various functions within buildings such as lighting and HVAC; see Intelligent building.
The platform has its origins with chip designs, power line and twisted pair signaling technology, routers, network management software, and other products from Echelon Corporation. In 1999 the communications protocol (then known as LonTalk) was submitted to ANSI and accepted as a standard for control networking (ANSI/EIA709.1-B). Echelon's power line and twisted pair signaling technology was also submitted to ANSI for standardization and accepted. Since then, ANSI/EIA709.1 has been accepted as the basis for IEEE 1473-L (in-train controls), AAR Electro-pneumatic braking systems for freight trains, IFSF (European petrol station control), SEMI (semiconductor equipment manufacturing), and in 2005 as EN14908 (European building automation standard). The protocol is also one of data link/physical layers of the BACnet ASHRAE/ANSI standard for building automation.
The acceptance of the LonTalk protocol as an ANSI standard fostered additional standards in various industries worldwide including, IEEE 1473-L (in-train controls), AAR Electro-pneumatic braking systems for freight trains, IFSF (European petrol station control), and SEMI (semiconductor equipment manufacturing). The protocol is also one of data link/physical layers of the BACnet ASHRAE/ANSI standard for building automation. More recently, in 2005 the European Community released the LonWorks based EN14908 building automation. In 1996, China ratified the technology as a national controls standard, GB/Z 20177.1-2006.
One of the keys to the interoperability of the system is the standardisation of the variables used to describe physical things to LonWorks, this standards list is maintained by the LonMark Internationaland each standard is known as Standard Network Variable Types (SNVTs, pronounced "snivets") so for example a thermostat using the temperature SNVT is expected to produce a number between zero and 65535 that equates to a temperature between -274 and 6279.5 degrees celsius.
