THE LOCAL CONTROL NETWORK WITHIN BUILDING AUTOMATION
The Local Control Network, basically a network for local control, is a proprietary system designed for automation of residential buildings and functional buildings. This network has been available since 1992 and has been mass produced since 1993. Each system is composed of a network with decentralized organization and formed from the LCN modules and the 4-wire bus. Here, the modules are also always equipped with the same hardware and software, which produces identical programming. Depending on the use, the modules are also available in different versions. However, they always have two outputs, which can be controlled and dimmed independent of each other. Within the Local Control Network it is possible to add actuators and sensors, but also pushbuttons and couplers, so that the network can be expanded.
The Modules of the Local Control Network
Several modules are required to be able to perform communication within a system based on the technology of the Local Control Network. In this case, modules of a segment are connected with four different conductors.
- Protective conductor
- Phase conductor
- Neutral conductor
- Conductor for data transmission
However, the communication itself requires only the neutral conductor in combination with a data wire. Max. 250 modules can be covered within one bus and its segments. These bus segments can again be combined via a higher level, which can accept up to 120 of such segments. Accordingly, the max. number of modules within a Local Control Network is 30000 modules. The bus of the LCN can also occur in different topologies, i.e. network structures:
- Line shape
- Star shape
- Tree shape
The Advantages of the Use of Modules with the Local Control Network
When the LCN is used for automation of processes in buildings, the system-internal communication takes place via modules. Because of the use of these power units, it is no longer necessary to add further components, with the result that connection can be made directly to the already laid in-wall cable. However, the use of modules is still based on the knowledge of further positive effects:
- Because of the combination of sensors and actuators, only few modules are required.
- Then only few rules and regulations have to be observed during the planning.
- Installation and programming can be implemented easily.
- The bus topology is very clear because of the clear shapes.
- Standard material can be used for the installation, so that the costs are lowered.
- Data losses within large installations can no longer occur, with the result that the Local Control Network is very powerful, especially as the data transfer is considerably faster than with other systems.
- Even the standard type in the system has feedback via switch access.
- Cost reduction also through elimination of the basic installation of a bus line, as multifunctional modules can be used, which are considerably cheaper.
The Fields of Application of the Local Control Network
Because of the open design and the flexibility within the network, LCN can be used not only for normal single-family houses, but also in larger office buildings. At these application locations, the bus system assumes numerous functions:
- Cost reduction by saving of energy through temperature control
- Monitoring of rooms
- Initialization of time-dependent controls, so that they can perform automatically
- Date representation for alarm messages by means of DIN processing
- Setup of a time recording system
- Access control
- Saving and recalling of light scenes and control of internal and external lighting
- Place automatic controls under environment influences, so that these function as a trigger
Moreover, all of these functions can be reprogrammed as desired, so that the Local Controls Network is an easy solution for building automation.
To sum up the Local Controls Network
The LCN is a bus system that can do without a separate bus line and that can be reprogrammed easily. Moreover, the result is a network suitable for the craft, where an installation bus is created that is perfectly suited for the automation of housing and functional buildings. The essential advantage over other bus systems lies in the fact that the usual additional bus line is simply replaced by another core of the standard NYM cable, so that no new wiring system is required any longer. Omitting the basic installation of a separate bus line is permitted only thanks to handling of the data core as a mains core, so that this may be led together with the 230 V installation. However, the importance of the Local Controls Network for industrial communication and for the information technology is based especially on the absence of numerous regulations, so that the only item to be observed during planning is the fact that the max. number of modules may not exceed 250. Depending on the type of installation, modules can then still be coupled with each other, so that an installation considered as especially compact can be realized by use of this network, which increases the functionality of the system.