What is an installation Bus in building automation term?

In a conventional electrical installation, each switch, button, light fixture, air conditioning system, alarm system, remote control, sensors, etc. are installed separately. Each of these devices perform limitted pre-wired function. Any expansion adds separe special wiring to the building. The amount of wires and connections in a conventional electrical installation grows exponentially with the increased controlabilities in the installation. Think about how much more wiring the 3-way or 4-way switch installation requires versus simple wiring of on/off switch. Up to a certain complexity, installation and maintenance cost becomes major problem for adding even a small expansion.

Installation Bus is a new and much better way to perform electrical installation in a building. In this concept, everything that is electrical can be placed on a "Bus" or a data communication line. Intelligent nodes on the Bus are capable of communicating using a messaging protocol with other nodes on the wiring. The results of this technology are:

  • The integration of all devices into one system. The whole electrical installation becomes simply laying out the Bus, the electrical wire that every new device can just tap on. Installation becomes very simple and cost effective, especially in large commercial and industrial installation. Whole building control becomes possible without extra wiring.
  • Devices such as sensors, switches, detectors are used much more effectively. In effect, any such installed devices can be utilized by any intelligent node anywhere on the Bus. For example, a window open detector can be used by the air conditioning system and the alarm system at the same time, for different purposes. The installation has therefore effectively more sensors and detectors than a conventional installation. Whole building control is much more effective and reliable.
  • Expanding the system is now is just expanding the Bus. The Bus is expanded by extending the communication wire.
  • Intelligent nodes on the Bus are programable and are capable of performing complex control tasks reliably due to the fact that they work with each other as an integrated system, eg. each node is aware of the whole system, while performing a local control task. This is one of the keys for safe and reliable building control operation. Due to the fact that there is no central controller for the whole system, failure can only effect local devices and can be located easily and quickly. Moreover, recovery after a total building power outage is very quick because each local node is up and running within seconds after power is restored.
What are the key features of the LCN installation bus technology?

LCN technology was developed to bring all installation bus advantages into building using only conventional hardware and normal electrician training. The system consists of few intelligent modules and a large number of sensors, drivers, detectors, switch adaptors, remote control, keyless switch, touch sensitive switches. As the results, LCN technology features:

  • Simple installation using only normal electrical wires that electrician are familiar with and know how to work with. No extra twisted wires, coaxial cables, wireless repeater, etc. need to be dealt with beside normal electrical wire. In addition, since a bus installation is basically a one electrical wire that every node taps on, the layout is much simpler than conventional installation that requires multiple wires connecting switches, lights and other devices. The result is much less electrical wires is used compared to conventional installation. The only thing required is using a cable with an extra wire, for example AWG14/3 instead of AWG14/2. The extra wire is the actual data Bus that the modules use to communicate with each other.
  • Each module is connected directly to the Bus and is self-sufficient. There is no extra power supply connection that needs to be worried about. The basic module (LCN-UPP) is small enough to fit into the regular wallswitch box or outlet box behind the mechanic. Other basic module (LCN-HU, LCN-SH) can be mounted on rail in the fuse cabinet or branch circuit cabinet. High load outputs up to 2KWatt are provided by adding high load relais to output of the basic modules.
  • All basic modules are intelligent (microprocessor driven), have non-volatile memory, are programable to perform highly sophisticated feedback-controled functionalities and have non-volatile storage for 100 preset "scenes".
  • Programing of the modules on the Bus is performed on PC running a mostly point-and-click software package called LCN-PRO.
  • All modules are protected against overvoltage on all inputs. Operation in the modules can bridge upto 20sec power supply failure. In essen, the LCN controlled building well protected against surges caused by power line and weather.
  • The large number of available peripherals modules allows large and flexible system configurations, basically covers all requirements residential, commercial and industrial buildings.
Why does LCN installation need one extra wire in the cable?
  Actually the question should be "How could that many benefits come from only one extra wire?". With only one extra wire in the standard electrical cable, LCN has achieved putting the fasttest, most reliable installation bus technology worldwide to work in the building. Other less reliable, slower building control systems required extra twisted wires or coaxial cable beside the standard electrical cable, making installation more costly and expansion more difficult. technologies that work without extra wire such as Power Line Carrier or Wireless building control technology are well known both for their unreliability and their limitted system size and coverage. These technologies can not be trusted in large residential installations, not to mention commercial and industrial buildings. But worse of all, these technologies are not cost effective because they also require lot of special wiring and special equipment to cope with the unreliability inherent in the underlying technologies. Other hardwired systems not only require more extra wires (two) and different kind of wires than the standard electrical cable, they also have a central controller which then require lot of cabling going to and from the central controller. The amount of cable used in these system is incredible making the installation very expensive. Worse, the operation is less safe and less reliable, because if the central controller fails, the whole building is down. Expansion is not easy in these installation either, because it requires adding wires running back to the central controller. In short, they key is that LCN technology offers many benefits with only one extra wire: low installation cost, most reliable system, easy expandability.
What makes LCN system so reliable?
  First off, LCN uses an open protocol that requires two-way communication between modules. Any command going from one module to the other requires an acknoledgment in return that the command has been executed. This ensures the integrity of the system. For example, a switch in the 30th floor of one building can be programmed to turned on the light in the hallway in the 15th floor of another building. If the module controlling the light does not send back the acknowledgement that the light is in fact turned on, the system can take an action that is programmed for such case (sounds peep, sends notification via email or SMS, flash some lights or turn on the error LED on the switch, etc.). Secondly, the LCN bus is a very fast bus. In the same example above, the delay between the pressing of the swich on the 30th floor of one building and the resutling light turned on the 15th floor is about few hundreds milliseconds. The bus and the protocol has been designed to withstand many folds of the surges and disturbances caused by outside enviroment and devices in the building. The system is simply robust. Furthermore, the maximum number of addressable modules on a single bus is 30,000. The installation in the 4th highest building in Europe only reaches 1/3 of that maximum. See the summary of the LCN specification.
Are LCN products UL approved?
  LCN Bus Modules are approved by UL as "Commercial Dimmer" under control number 28KH.

How difficult is retrofitting existing wiring with LCN?
  All of LCN intelligent modules are autonomous and can work without talking to any other modules. As such, they can be installed invidually to controlled locally connected devices. But if the advantages of sharing controls between modules on an installation bus is important, then the modules have to be connected together with the extra wire. Note that in this case, the extra wire could be just a thin low voltage wire. The strong solid extra wire in the electrical cable in new construction is for convinient purpose only. LCN bus signal is in the 30V range. For a retrofitting project, it is also possible to create individual "buses" such as the landscaping controlling modules on one bus, living room and kitchen in another, etc. Most of the time, connecting the modules with one low voltage thin wire is not a problem. The system benefits are far greater than the cost of the effort.
What kind of wallswitches and touch buttons style can LCN provide?
  LCN does not manufacture proprietary wallswitches and buttons. LCN modules are designed to accept binary inputs from all wallswitches and buttons from other manufacturers. LCN modules work with all available wallswitches and touch buttons available on the market. Leviton, Lutron and other companies have large selections available for the American market. If customers prefer also German distinctive high quality wallswitches and buttons made by companies such as Jungs, Berker, Siemens, GIRA, Bush-Jaeger, etc., we can offer full catalogs for customer selection.
Does LCN provide a color LCD with touch screen user interface to control the system?
The LCN bus protocol is open and thus anyone can make an LCD touch screen user interface for the system. Many partners of LCN such as Crestron offer such add-on device. Per inquiry we can provide contact information for our customers to get a list of LCD touch screen devices for selection.
Can LCN system be controlled over the internet or via cellphone or via PDA?
  Yes. Internet access to LCN system can be realized in many ways. A direct way is to use a PC that is running LCN software accessing the LCN bus using the LCN-PC module. If this PC is on the Internet, it can provide direct access to the LCN system via few software mechanism. An indirect access to LCN via Internet is using gateways manufactured both by LCN and other companies that bridge LCN system to systems that can be controlled over the Internet. This will work in an environment where LCN system is installed together with another system. LCN also has software that triggers SMS messages to be sent to cellphones to notify some status of the system. For example, the system can be programmed to notify registered cellphones when a window is opened at night while the alarm system is armed. Many partners of LCN also offer complete user interface for LCN system on PDA connecting via Bluetooth. We can provide a complete list of such devices upon request. Phillips also offer a universal remote control device that work flawlessly with the LCN-RR IR Receiver, allowing an integrated control of LCN with home entertainment systems.
Can LCN work together with other building automation systems?
  Yes. Gateways to other building automation systems are offered by LCN as well as by other third party vendors. In fact, in most old buildings there are likely some legacy or costly technology already installed. Migration to LCN can happen gradually by expanding the new LCN to take over the old system. LCN will be happy to assist you with the migration per request.
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