Local Operating Network
Local Operating Network ( LON ) is a standard for a fieldbus that is mainly used in building automation .
LON was developed by the US company Echelon Corporation around 1990. This technology has been recognized by the IEC and ISO as an international standard since December 2008 and documented in the 14908-x series of standards, after it was already listed as a European standard under the same code numbers. At that time, more than 100 million devices were installed with this technology. LON is used, for example, in the Willis Tower , at Frankfurt am Main Airport , Post Tower Bonn, to control Oslo street lighting and in the Reichstag building.
concept
The original core idea of the LON field bus system was decentralized automation in flat, i.e. H. not or only little vertically subdivided systems. In LON devices to communicate (in the terminology node or engl. Nodes called) via a bus. The conceptual approach of decentralized automation with LON provides for the nodes to be subdivided into sensors , actuators and controllers . Only information that is required locally should be processed "on the spot" if possible. This concept is in contrast to hierarchically oriented systems in which a superordinate computer (usually a programmable logic controller - Direct Digital Control - station) collects all data.
hardware
The heart of this fieldbus system on the hardware side is the neuron (chip). The Neuron chip contains three 8-bit processors (CPUs):
- The Media Access CPU controls the physical connection to the network.
- The network CPU is responsible for encoding and decoding the network messages.
- The software programmed by the user, which represents the actual "intelligence" of a node, runs on the application CPU.
Each Neuron chip contains a 48-bit long ID number (the Neuron ID ) that is unique in the world and with the help of which each bus node in the network can be clearly identified. The Neuron chip was initially manufactured by both Motorola and Toshiba . At the beginning of 2001, however, Motorola stopped production of the Neuron chip. Cypress and Echelon were added . Solutions are now also available in which the LON protocol stack runs on other processors (e.g. ARM7 ).
The communication protocol of this fieldbus is called the LonTalk protocol. The LonTalk protocol defines layers 2 to 7 of the OSI reference model. Various transceivers are available for the physical layer (layer 1 of the OSI model ), such as wired transmission, radio, fiber optics, but also powerline communication.
The data coding on the physical layer can be controlled directly by the Neuron chip or by the transceiver itself. The LonTalk protocol offers the Direct Mode operating mode for direct control. The data is encoded in the Manchester code . A modified p-persistent CSMA with optional collision detection is used as the access method , with the possibility of prioritizing individual messages. In special purpose mode, transceivers can be controlled with their own signal processing. In this mode, the transceiver itself controls the media access. This field bus system is basically a multi-master system.
From a logical point of view, the nodes communicate with one another via communication objects, so-called Network Variables (NV). So-called SNVTs (Standard Network Variable Types) are defined so that nodes from different manufacturers can communicate with one another . These are data types from the user's point of view, e.g. B. the type SNVT_temp_p, which embodies a temperature. The organization that drives this forward is LonMark International .
software
On the software side, nodes with applications for standard tasks or freely programmable systems are used. For the applications with standard tasks, the network interface and - if necessary - also the tasks in LonMark are standardized or recommended. The tasks are divided into LonMark objects - also known as functional profiles . Examples are the Lamp Actuator , the Switch and the Constant Light Controller object. Free programming takes place e.g. Partly via Neuron C (e.g. with the NodeBuilder from Echelon), an ANSI C extension or via graphic programming (e.g. with the IPOCS programming system from SysMik).
Network management tools are used to define the communication between the devices (the “binding”), commissioning and management in LON networks. Network interfaces of various types are used for physical access to the LON networks. a. PC plug-in cards.
LonWorks Network Services (LNS), a client / server architecture with an integrated database, has established itself for the software management of the information . For the connection to the building management system (BMS) - or in the general language of automation to SCADA systems ( Supervisory Control and Data Acquisition ) - there are interfaces that correspond to the state of the art, e.g. B. via OLE for Process Control (OPC).
As with some other bus systems, the LON topology allows controllers (products) from different manufacturers to be combined with one another. Various LNS network management tools from various manufacturers (e.g. LonMaker from Echelon, NL220 from Newron System, ALEX from spega or CARE from Honeywell) are available to parameterize the devices and create the bindings. They differ both in the type of graphic representation of the LON network and in the scope of the management services offered.
When using the LNS architecture from Echelon, license fees (device credits) must be paid once for each node integrated into the network. To avoid these costs, some manufacturers have developed network management systems that are not based on LNS. Examples of such systems are NLStart from Newron System, the NiagaraAX framework from Tridium and Honeywell CARE.
Frameworks
- OSGi - Middleware standard (Java framework) for the integration of LON in service gateways
Organizations
The international organization of the manufacturers, integrators and users of LON technology is LonMark International , based in San Jose, California, USA.
A user organization is active for LON in Germany , LonMark Germany (formerly "LON User Organization eV LNO"). Almost all known manufacturers of LON devices and recognized specialists in this field are listed in LonMark Germany.
So-called LonMark Affiliates are also active in other European countries as well as in Asia and America.
The European LonMark Affiliates are organized in LonMark Europe.
Norms and standards
The current DIN EN 14908 series is in German-speaking countries. There will soon be an international standard for which the final draft is in the global vote, cf. ISO / IEC FDIS 14908 series (not listed here).
- DIN EN 14908-1: 2007-11 - Company-neutral data communication for building automation and building management - Building data network protocol - Part 1: Data protocol layer model; English version EN 14908-1: 2005 . Beuth, Berlin 2007.
- DIN EN 14908-2: 2006-01 - Company-neutral data communication for building automation and building management - Building data network protocol - Part 2: Communication via twisted-pair cables; English version EN 14908-2: 2005 . Beuth, Berlin 2006.
- DIN EN 14908-3: 2007-02 - Company-neutral data communication for building automation and building management - Building network protocol - Part 3: Communication via power supply lines; English version EN 14908-3: 2006 . Beuth, Berlin 2007.
- DIN EN 14908-4: 2007-02 - Company-neutral data communication for building automation and building management - Building network protocol - Part 4: Communication using Internet protocol (IP); English version EN 14908-4: 2006 . Beuth, Berlin 2007.
literature
- Dietrich, Loy, Schweinzer (ed.): LON technology. Distributed systems in use . Hüthig, Heidelberg 1998, ISBN 3-7785-2581-6 .
- LonWorks Installation Guide. LonWorks practice for electrical engineers . VDE Verlag, Berlin 2000, ISBN 3-8007-2575-4 .
- LonWorks planning manual for planners, architects and operators . VDE Verlag, Berlin / Offenbach 2001, ISBN 3-8007-2599-1 .
Web links
Individual evidence
- ↑ a b LON Achieves ISO / IEC Standardization . LonMark International. Retrieved June 16, 2009.
- ↑ LonWorks at Work in Buildings Around the World (PDF) Echelon Corporation. Archived from the original on May 30, 2009. Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved June 16, 2009.
- ↑ Oslo Street Lighting System Slashes Energy Use with LonWorks® Technology (PDF) Echelon Corporation. Retrieved October 22, 2015.
