Das Local Opening Network

LON is the abbreviation of Local Opening Network, which is a technology for networks that makes it possible to connect devices of different manufacturers with each other and to link them together. This makes it possible to network devices that otherwise have nothing in common, so that a system is created that is openly accessible and thus offers more efficiency and economy.

The principle employed with the Local Opening Network

This network technology was developed based on the principle of distributed intelligence. This means that the sensors and actuators, i.e. the nodes of a connection, each have an own chip, which can be programmed individually and freely. This chip, which is also called a neuron, is composed of three CPU cores, which serve the main processor. Two of these chips are used for connection of the buses and are also in charge of the protocol. The remaining chip is used by the application programs.
The sensors and actuators in the Local Opening Network can be arranged in various topologies, which are the structural networking of all participants and components. Furthermore, different media can be used for the transmission and the coupling of the nodes, which among other things include the following:

  • Two-wire line
  • Radio
  • Optical waveguides
  • Power lines

Communication with the Local Opening Network

Within the LON network, data is transmitted independent of the center, as the nodes can exchange information directly with each other and thus can trigger actions inside the system independently and as desired. This is done using a uniform communication protocol called LonTalk. The standardized network variables are also used. LonTalk defines the layers 2 to 7 of the OSI reference model. The remaining physical layer of the first layer is operated via various transceivers, which can cover the range from line-bound transmission to wireless and glass fibers. The coding of the data on the first layer is then controlled directly by the transceivers or optionally also the neuron chip. The coding taking place over the Local Opening Network is done via the operation mode “Direct Mode”, where the data is encrypted according to the Manchester code. With this, there is the option to prioritize certain messages within the communication, so that their handling has priority.

Conditions for meaningful use of the Local Opening Network

The special characteristic provided by the LON networks lies in the absence of a local limitation. This means that the system can be operated remotely via the Internet from a computer at a different location. This form of checking and control makes it possible to create a network that can connect the systems even across different locations and over long distances to a unit. This is profitable especially for companies located at several sites, but their networks still have to communicate with each other. However, for optimal use of the Local Opening Network, two essential factors must be observed:

  • Interoperability
  • Cross-product planning

Interoperability represents an essential technological precondition for the creation of an LON network that also brings a high degree of functionality with it. Here, the interoperability stands for the aspect of cooperation of devices of different manufacturers. Accordingly, the target of this technology is also behind this requirement. When these conditions are guaranteed, the network can be assumed as open and freely available for manufacturers as well as users. The second point is the cross-product planning, which not only underlines the viewpoint of interoperability, but rather specifies that a system that wants to function on the basis of LON must also think holistically. Together with the cross-product thinking, planning is also at the center, as support of the planner by the system integrators must be offered in regard to the practical implementation. The Local Opening Network can only be used properly if this is possible.

To sum up the Local Opening Network

The essential advantage of the use of the Local Opening Network lies in the realization of different applications of many sectors. In addition to building and home automation, LON is also found in industry and process automation. Especially for the automation of processes on buildings, the network effectively concentrates devices of heating, ventilation, and lighting. By means of

  • Switching programs operating time- and event-oriented and
  • energy management and
  • visualization of building data,

savings in regard to the energy costs and increase in value by easy operation and increased comfort can be made. Furthermore, sensors can be used repeatedly, and it is possible to use multiple actuators. And finally, the expenses of wiring can be minimized by the ability to expand the networking of a building system thanks to the modular construction of the Local Opening Network.