LonWorks

Local Operating Network (LON ) is a standard for a fieldbus, which is mainly used in building automation.

LON was developed by the U.S. company Echelon Corporation around 1990. Since December 2008, this technology is recognized by the IEC and the ISO as an international standard and 14908 -x documented in the standard series, after it has been performed as a European Standard under the same Root. At this time, more than 100 million devices were installed with this technology. LON example, in the Sears Tower, used at the airport of Frankfurt am Main, to control the Oslo street lighting and in the Reichstag building.

Concept

The original core idea of the LON field bus system was decentralized automation in shallow, that little or no vertical split systems h. The LON communication devices (in the terminology called nodes or engl. Nodes) on a bus. The conceptual approach of decentralized automation with LON provides a subdivision of nodes in sensors, actuators and controller. Local only required information is to be further processed as possible to " spot ". This concept is in contrast to hierarchically oriented systems, in which a higher-level computer (typically a programmable logic controller - Direct Digital Control - Station) all data collecting.

Hardware

Hardware -sided core of this field bus system is the neuron ( chip). The neuron chip comprises three 8 -bit processors ( CPUs):

• The media access CPU controls the physical connection to the network.
• The network CPU is responsible for the encoding and decoding of the network messages.
• On the application CPU, the user-programmed software which represents the real " intelligence" of a node is running.

Each neuron chip contains a globally unique 48-bit ID number ( the Neuron ID), with the help of each bus node is uniquely identified in the network. Neuron chip was first prepared both by Motorola and by Toshiba. In early 2001, Motorola introduced, however, a production of the Neuron chip. Newly arrived Cypress and Echelon. In the meantime, solutions are available in which the LON protocol stack on other processors (e.g., the ARM7 ) runs.

The communication protocol of this field bus is called LonTalk protocol. The LonTalk protocol defines the layers 2-7 of the OSI reference model. For the physical layer ( layer 1 of the OSI model ) different transceivers are available, such as line transmission, radio, optical fiber but also powerline communication.

The data coding at the physical layer can be controlled directly by the Neuron Chip or by the transceiver itself. For the direct control of the LonTalk protocol provides the mode Direct Mode. The coding of the data occurs in the Manchester code. As the access method, a modified p- persistent CSMA is used with an optional collision detection, whereby it is possible to prioritize individual messages. In the Special Purpose fashion transceiver can be controlled with its own signal processing. In this mode, the transceiver itself takes over the control of media access. Basically, this field system is a multi- master system.

From a logical point of view the so-called Network nodes via communication objects communicate with each other Variables (NV). Thus, nodes from different manufacturers can communicate with each other, so-called SNVTs ( Standard Network Variable Types ) can be defined. These are data types from the user's perspective, such as the type SNVT_temp_p embodying a temperature. The organization that promotes this, is the LonMark International.

Software

On the software side node used with applications for standard tasks or programmable systems. Where necessary - - For applications with standard tasks the network interface and standardized or recommended the tasks in LonMark. The tasks are in LonMark objects - also referred to as functional profiles (functional profiles ) - divided. Examples are the lamp actuator, the switch and the constant light controller object. Free programming is done partly on neuron C (eg with the NodeBuilder Echelon ), an ANSI C extension or via a graphical programming (eg with the programming system IPOCS the SysMik ).

For setting up the communication between the devices ( the "binding " ), commissioning and management in LON networks network management tools are used. For physical access to the LON network network interfaces of various types are used, including PC cards.

For the software engineering management of information to LONWORKS Network Services ( LNS) has enforced a client / server architecture with an integrated database. For the connection to the building management system (BMS ) - or in the general way of speaking of automation to SCADA systems ( Supervisory Control and Data Acquisition) - are interfaces, as they are known in the art, eg, via OLE for Process Control (OPC ).

As with some other bus systems allows the LON topology to combine controllers (products) from different manufacturers. To parameterize the device and establishing the various bindings LNS Netzwerkmanagementools are from different manufacturers (eg LonMaker, Echelon, NL220 Newron system, ALEX spega or CARE Honeywell ) are available. They vary by the type of graphical representation of the LON network and by the scope of offered Management Services.

When using the LNS architecture of Echelon unique royalties (Device credits) must be paid for each node connected to the network. To avoid these costs, some manufacturers network management systems have developed that are not based on LNS. Examples of such systems are NLStart the company Newron system that NiagaraAX framework of the company Tridium and Honeywell CARE.

Frameworks

• OSGi - middleware standard ( Java Framework) for the integration of LON in Services Gateways

Organizations

The international organization of manufacturers, integrators and users of LON technology is LonMark International, based in San Jose, California, USA.

In Germany, a user organization for LON is active, the LonMark Germany (formerly " LON user organization eV LNO "). Almost all known manufacturers of LON devices and recognized specialists in this field are listed in the LonMark Germany.

So-called LonMark Affiliates are also active in other European countries, Asia and America.

The European LonMark Affiliates organize themselves in the LonMark Europe.

Norms and Standards

Currently, the DIN EN 14908 series in Germany. Soon there will be an international standard to the lies of the final design in the global vote, see ISO / IEC FDIS 14908 series ( not listed here ).

• DIN EN 14908-1:2007-11. Open Data Communication in Building Automation and Building Management - Control Network Protocol - Part 1: Data protocol layer model; English version EN 14908-1:2005. Beuth, Berlin, 2007.
• DIN EN 14908-2:2006-01. Open Data Communication in Building Automation and Building Management - Control Network Protocol - Part 2: Communication via twisted pair cables; English version EN 14908-2:2005. Beuth, Berlin, 2006.
• DIN EN 14908-3:2007-02. Open Data Communication in Building Automation and Building Management - Control Network Protocol - Part 3: Communication through the power supply lines; English version EN 14908-3:2006. Beuth, Berlin, 2007.
• DIN EN 14908-4:2007-02. Open Data Communication in Building Automation and Building Management - Control Network Protocol - Part 4: Communication using Internet Protocol ( IP); English version EN 14908-4:2006. Beuth, Berlin, 2007.