C-Bus (protocol)
Encyclopedia
C-Bus is a proprietary communications protocol for home and building automation that can handle cable lengths up to 1000 meter using Cat-5 cable. It is used in Australia
, New Zealand
, Asia
, the Middle East
, Russia
, USA, South Africa
, the UK and other parts of Europe including Greece
and Romania
. C-Bus was created by Clipsal
's Clipsal Integrated Systems division (now part of Schneider Electric
) for use with its brand of home automation and building lighting control system. C-Bus has recently become available in the USA under the 'SquareD Clipsal' brand name.
C-Bus is used in the control of domotics, or home automation
systems, as well as commercial building lighting control systems.
Unlike the more common X10
protocol which uses a signal imposed upon the AC power line
, C-Bus uses a dedicated low-voltage cable or two-way wireless network to carry command and control signals. This improves the reliability of command transmission and makes C-Bus far more suitable for large, commercial applications than X10.
and can also be interfaced to a home security system, AV products or other electrical items. The C-Bus system is available in a wired version and a wireless
version, with a gateway available to allow messages to be sent between wired and wireless networks.
The wired C-Bus system uses a standard category 5 UTP (Unshielded Twisted Pair) cable as its network communications cable. Clipsal manufactures a specific category 5 cable for use within electrical distribution panels. This cable has a pink outer sheath which is rated to ensure adequate electrical isolation between the mains voltages found in distribution panels and the extra low voltage C-Bus. Outside of distribution panels standard category 5 UTP cable can be used.
The category 5 C-Bus network wiring uses a free topology architecture. The maximum length of cable used on a C-Bus network is 1000 metres; however this is easily extended using C-Bus Network Bridges. Up to 100 units can be installed on a C-Bus network and this can also be extended using Network Bridges.
The maximum number of C-Bus networks in one installation is 255 (note that this limitation does not apply if a C-Bus Ethernet Interface is utilised, the system size is then limited to IP Addressing only). The maximum number of networks connected in series to the local network via Network Bridges is seven (i.e. using six network bridges).
Each standard C-Bus unit requires 18mA @ 15-36Vdc to operate, however some C-Bus units require up to 40mA.
More than one C-Bus power supply can be connected to a C-Bus network to provide sufficient power to the C-Bus units, the C-Bus power supplies will share the load evenly.
Each C-Bus network requires a network burden if there are insufficient C-Bus units on the network. This network burden can be enabled on C-Bus output units through software or a hardware burden can be connected to the network.
Each C-Bus network requires at least one system clock generating unit for data synchronisation.
The isolation between the mains supply circuitry and the 36V DC C-Bus circuitry is greater than 3.5kV. This is achieved using double wound transformers and opto isolators. This means the C-Bus wiring, connections and circuitry can be considered Extra Low Voltage.
In C-Bus systems, the connections between the DB and (for example) the ceiling lights, and between the DB and the junction box (wall switch) are completely separate. In addition, there are no connections between the Junction Box and the respective ceiling lights.
The power control in a C-Bus system lies in a “Dimmer” or “Relay” which is installed in the DB and replaces the traditional switch used in conventional wiring. This Dimmer (or Relay) has a 120/220V Line interconnection directly to the ceiling light and a neutral connection back from the ceiling light to the Dimmer. The Dimmer will control the light directly and will receive its commands from another device on the C-Bus network (for example, a wall mounted light switch/keypad). This wall mounted light switch would not be connected to any load whatsoever; it would be directly connected with the Dimmer by means of a control/signaling cable. The Dimmers normally come as 4-, 8- or 12-channel DIN-rail mounted devices.
Using one of Clipsal's C-Bus interface modules (PCI for RS232 or USB and CNI for Ethernet TCP/IP), you can interact with other home automation systems, or with applications on devices like Android, iPad or iPhone. All you do is plug a network cable from your Home WiFi router to the Clipsal C-Bus Ethernet module, and then any Android or iPad can control your home automation system. You can also use this same method to integrate C-Bus with HomeSeer using MCSxAP. And in theory you can also do this to integrate C-Bus via a X10 module for the PC.
If you are a .Net/Java/c++ software developer, you can find the C-Bus protocol information here to interact from your PC: http://www2.clipsal.com/cis/technical/downloads
The C-Bus protocol was developed using the ISO 7 layer reference model. C-Bus supports a number of interfaces such as RS232 and TCP/IP and makes these protocols available to third party companies. Clipsal has also developed a server application called C-Gate, to facilitate software integration. The C-Bus interface specifications are available at no-cost through the C-Bus Enabled Program, however it is necessary to agree to a license agreement. It is also possible to become a C-Bus enabled partner; This requires payment but provides a greater level of support for product development and certification.
(Sydney Opera House etc.). C-Bus is currently available in Asia
, the United Kingdom (installed in Number 10 Downing Street, Wembley Stadium
and Manchester City Football Club), Russia
, USA (named SquareD), Canada
(from Sound Developments Ltd) and a number of other countries are now using this system. One major obstacle to widespread use of wired C-Bus is that it will not work with a standard mains wire installation, a completely new wiring system must be installed for a wired C-Bus system which means that it is normally only used for new builds. The C-Bus wireless (RF) system can however be retrofitted using the existing mains wiring.
C-Bus is compatible with OPC, DALI
, DSI, BACnet, TCP/IP, Crestron, AMX, RTI, LonWorks, ModBus, Charmed Quark Controller, the Comfort Intelligent Home System and some other protocols through interfaces.
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
, Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, USA, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, the UK and other parts of Europe including Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
and Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
. C-Bus was created by Clipsal
Clipsal
Clipsal is an Australian brand of electrical accessories. The main factory was located at Bowden, but it was announced in 2008 that a move would be made to a new site, located at Gepps Cross. The move took place in 2009. Clipsal also boasts smaller factories in Nuriootpa, Strathalbyn and Wingfield...
's Clipsal Integrated Systems division (now part of Schneider Electric
Schneider Electric
Schneider Electric is a French global company. It was founded in 1836 by two brothers, Eugène and Adolphe Schneider.In the first part of the 20th century, Schneider et Cie associated itself with Westinghouse Systems, a major international electrical group at the time. The group began manufacturing...
) for use with its brand of home automation and building lighting control system. C-Bus has recently become available in the USA under the 'SquareD Clipsal' brand name.
C-Bus is used in the control of domotics, or home automation
Home automation
Home automation is the residential extension of "building automation". It is automation of the home, housework or household activity. Home automation may include centralized control of lighting, HVAC , appliances, and other systems, to provide improved convenience, comfort, energy efficiency and...
systems, as well as commercial building lighting control systems.
Unlike the more common X10
X10 (industry standard)
X10 is an international and open industry standard for communication among electronic devices used for home automation, also known as domotics. It primarily uses power line wiring for signaling and control, where the signals involve brief radio frequency bursts representing digital information...
protocol which uses a signal imposed upon the AC power line
Power line communication
Power line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...
, C-Bus uses a dedicated low-voltage cable or two-way wireless network to carry command and control signals. This improves the reliability of command transmission and makes C-Bus far more suitable for large, commercial applications than X10.
C-Bus System
The C-Bus System can be used to control lighting and other electrical systems and products automatically or via remote controlRemote control
A remote control is a component of an electronics device, most commonly a television set, used for operating the television device wirelessly from a short line-of-sight distance.The remote control is usually contracted to remote...
and can also be interfaced to a home security system, AV products or other electrical items. The C-Bus system is available in a wired version and a wireless
Wireless
Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...
version, with a gateway available to allow messages to be sent between wired and wireless networks.
The wired C-Bus system uses a standard category 5 UTP (Unshielded Twisted Pair) cable as its network communications cable. Clipsal manufactures a specific category 5 cable for use within electrical distribution panels. This cable has a pink outer sheath which is rated to ensure adequate electrical isolation between the mains voltages found in distribution panels and the extra low voltage C-Bus. Outside of distribution panels standard category 5 UTP cable can be used.
The category 5 C-Bus network wiring uses a free topology architecture. The maximum length of cable used on a C-Bus network is 1000 metres; however this is easily extended using C-Bus Network Bridges. Up to 100 units can be installed on a C-Bus network and this can also be extended using Network Bridges.
The maximum number of C-Bus networks in one installation is 255 (note that this limitation does not apply if a C-Bus Ethernet Interface is utilised, the system size is then limited to IP Addressing only). The maximum number of networks connected in series to the local network via Network Bridges is seven (i.e. using six network bridges).
Each standard C-Bus unit requires 18mA @ 15-36Vdc to operate, however some C-Bus units require up to 40mA.
More than one C-Bus power supply can be connected to a C-Bus network to provide sufficient power to the C-Bus units, the C-Bus power supplies will share the load evenly.
Each C-Bus network requires a network burden if there are insufficient C-Bus units on the network. This network burden can be enabled on C-Bus output units through software or a hardware burden can be connected to the network.
Each C-Bus network requires at least one system clock generating unit for data synchronisation.
The isolation between the mains supply circuitry and the 36V DC C-Bus circuitry is greater than 3.5kV. This is achieved using double wound transformers and opto isolators. This means the C-Bus wiring, connections and circuitry can be considered Extra Low Voltage.
Wiring Design of C-Bus Systems
With conventional wiring, the mains power (120V/220V/240V) is wired from the Distribution Board (DB) to the load (for example, a ceiling light) via a wall switch.In C-Bus systems, the connections between the DB and (for example) the ceiling lights, and between the DB and the junction box (wall switch) are completely separate. In addition, there are no connections between the Junction Box and the respective ceiling lights.
The power control in a C-Bus system lies in a “Dimmer” or “Relay” which is installed in the DB and replaces the traditional switch used in conventional wiring. This Dimmer (or Relay) has a 120/220V Line interconnection directly to the ceiling light and a neutral connection back from the ceiling light to the Dimmer. The Dimmer will control the light directly and will receive its commands from another device on the C-Bus network (for example, a wall mounted light switch/keypad). This wall mounted light switch would not be connected to any load whatsoever; it would be directly connected with the Dimmer by means of a control/signaling cable. The Dimmers normally come as 4-, 8- or 12-channel DIN-rail mounted devices.
C-Bus Interoperability
As of 9 December 2008 Clipsal opened its C-Bus protocols to anyone who wants to interact with it programatically.Using one of Clipsal's C-Bus interface modules (PCI for RS232 or USB and CNI for Ethernet TCP/IP), you can interact with other home automation systems, or with applications on devices like Android, iPad or iPhone. All you do is plug a network cable from your Home WiFi router to the Clipsal C-Bus Ethernet module, and then any Android or iPad can control your home automation system. You can also use this same method to integrate C-Bus with HomeSeer using MCSxAP. And in theory you can also do this to integrate C-Bus via a X10 module for the PC.
If you are a .Net/Java/c++ software developer, you can find the C-Bus protocol information here to interact from your PC: http://www2.clipsal.com/cis/technical/downloads
The C-Bus protocol was developed using the ISO 7 layer reference model. C-Bus supports a number of interfaces such as RS232 and TCP/IP and makes these protocols available to third party companies. Clipsal has also developed a server application called C-Gate, to facilitate software integration. The C-Bus interface specifications are available at no-cost through the C-Bus Enabled Program, however it is necessary to agree to a license agreement. It is also possible to become a C-Bus enabled partner; This requires payment but provides a greater level of support for product development and certification.
The future of C-Bus
C-Bus as a home automation and building lighting control system is used primarily in AustraliaAustralia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
(Sydney Opera House etc.). C-Bus is currently available in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, the United Kingdom (installed in Number 10 Downing Street, Wembley Stadium
Wembley Stadium
The original Wembley Stadium, officially known as the Empire Stadium, was a football stadium in Wembley, a suburb of north-west London, standing on the site now occupied by the new Wembley Stadium that opened in 2007...
and Manchester City Football Club), Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, USA (named SquareD), Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
(from Sound Developments Ltd) and a number of other countries are now using this system. One major obstacle to widespread use of wired C-Bus is that it will not work with a standard mains wire installation, a completely new wiring system must be installed for a wired C-Bus system which means that it is normally only used for new builds. The C-Bus wireless (RF) system can however be retrofitted using the existing mains wiring.
C-Bus is compatible with OPC, DALI
Digital Addressable Lighting Interface
Digital Addressable Lighting Interface is a technical standard for network-based systems that control lighting in buildings. It was established as a successor for 0-10 V lighting control systems, and as an open standard alternative to Digital Signal Interface , on which it is based...
, DSI, BACnet, TCP/IP, Crestron, AMX, RTI, LonWorks, ModBus, Charmed Quark Controller, the Comfort Intelligent Home System and some other protocols through interfaces.
External links
- cbusforums.com — A community for users of C-Bus.
- C-Bus Enabled Program — Program for accessing the C-Bus protocol.
- CIS Software Downloads — Free software for programming and c ommunicating via C-Bus.
- CIS Technical Support — Technical information and support services for C-Bus products.