LON is one of the leading systems for building automation. LON is used worldwide and is also used in industrial applications and for tasks outside of building automation.
With LON you get a reliable, secure and efficient data transmission. LON is characterized by a high packet rate, data backup, authentication and the variety of interoperable data types.
LON is an open protocol. When selecting components, the installer is not limited to one manufacturer, but can choose from several hundred suppliers worldwide.
LON technology is standardized worldwide as ISO / IEC 14908 – including all different transmission media.
The worldwide standardization of the LON protocol and the certification of interoperability guarantee you maximum investment security.
LON has the right transmission medium for every task. The uniformity of the protocol in all media freed from constraints in planning.
With a Neuron chip and NodeBuilder software, LON technology can be easily integrated into your device.
The LON technology is based on the following basic insights: Technological advances enable ever smaller and at the same time more intelligent components and controls that can be used almost anywhere. Central control is no longer required. Increasingly complex requirements for control and monitoring functions must be subdivided into subobjects so that transparency and scope for variation are maintained. Distributed intelligence promotes this breakdown. Increasing cost pressure requires standardized and modular systems that can be quickly and easily built, expanded or modified, and that rely on existing infrastructures. As a result, LON networks are characterized by their functions not being centrally controlled but each distributed node having freely programmable intelligence. The decentralized control system keeps the overall system modular and flexible. Sensor and control telegrams are transmitted in topologies of any kind and with the most diverse media. Their status and command information can trigger actions at any location and at any participant within the LON network. In the field of building automation, for example, access controls, heating and lighting systems can communicate via LON. Interdependencies between the individual trades can be taken into account.
In order to achieve economical and standardized deployment, Echelon designed the Neuron® core. The Neuron name was chosen to point out the similarities between proper network control implementation and the human brain. There is no central point of control in the brain. Millions of neurons are networked together, each providing information to others through numerous paths. Each neuron is typically dedicated to a particular function, but loss of any one does not necessarily affect the overall performance of the network.
The Neuron core is available as a standalone component called the Neuron Chip. To further reduce device costs, Echelon also provides Neuron cores combined with communication transceivers, which are called Smart Transceivers.
To the developer and the integrator, the beauty of the Neuron core and Smart Transceivers lies in their completeness. The built-in communication protocol and processors removes the need for any development or programming in these areas. The Smart Transceivers eliminate the need to develop or integrate a communications transceiver. The Neuron core provides layers 2 through 6 of the ISO/OSI reference model of a communication protocol, and the Smart Transceiver adds layer 1. The device manufacturer only has to supply the application layer programming and the network integrator provides the configuration for a given network installation. This standardizes implementation and makes development and configuration simple and fast.
Most LONWORKS devices take advantage of the functions of the Neuron core and use it as the control processor. The Neuron core is a semiconductor component specifically designed for providing intelligence and networking capabilities to low-cost control devices. The Neuron core includes up to four processors that provide both communication and application processing capabilities. Two processors execute the layer 2 through 6 implementation of the ISO/IEC 14908-1 protocol and the third executes layer 7 and the application code. LONWORKS 2.0 Neuron cores add a fourth processor for interrupt processing. The device manufacturer provides application code to run on the Neuron core and I/O devices to be connected to the Neuron core.
The Neuron core is a system-on-a-chip with multiple processors, memory, and communication and I/O subsystems. At the time of manufacture, each Neuron core is given a permanent unique-in-all-the-world 48-bit code, called the Neuron ID. A large family of Neuron Chips is available with differing speeds, memory type and capacity, and interfaces. Approximately 30 million Neuron cores have been shipped as of early 2009.
A complete operating system including an implementation of the ISO/IEC 14908-1 protocol, called the Neuron firmware, is available for the Neuron core.
Topologies of LON networks do not have to follow any particular structure. Star, ring, tree or classic line structures can be chosen freely. In practice, this often results in free topologies, which are based on existing structures in buildings or facilities. For the segmentation of such free topologies, routers can be used to control the data exchange.
The LON technology is also extremely flexible in the choice of network cabling. So today almost all transmission paths are available:
Growing importance has the 230 volt power grid. Because here a LON network can be set up without any additional cabling. The communication then takes place via the available CENELEC frequency bands C or A. The transceivers PLT-22 or PLT 30 are available for frequency modulation. In the case of the PLT-22, transmission speeds of up to 4.8 kbps are achieved in the CENELEC Band C.
A LON network consists of up to 32,000 intelligent network nodes that communicate via LonTalk, regardless of the multitude of possible functions. LonTalk is a protocol developed by Echelon. It navigates the messages of the sensors and actuators through the network at a transmission rate of up to 1.25 Mbit / s. Time-critical messages are given priority. Secure transmission is ensured, among other things, by end-to-end control and acknowledgments. If these do not arrive, the message is repeated until all recipients have responded.
In addition to bus safety, this system also attaches importance to the recording of events and their evaluation. Events can, for example, be linked with each other with a time stamp, in turn they can be used to control outputs or to be assigned to output texts, such as warning information, alarm or message texts.
Thanks to this decentralized intelligence, smaller and larger LON networks can be operated inexpensively without host computers or PLCs (for centralized recording and evaluation). For control and monitoring tasks, a host computer is not required.
Without further processing of the LON bus signals, lines of up to 2 kilometers can be operated. When using physical star couplers, for example, the range of the individual spur lines is a maximum of 1.3 kilometers. In addition, the structure of the bus network can be extended by repeaters, routers or gateways so that an almost unlimited length can be achieved.
For building automation, LON offers a flexible fieldbus system with decentralized logic that can reach large ranges with a wide variety of media at a high level of security. Due to the modular design, the commissioning as well as the modification and expansion of the network is always flexible and possible without much effort.