CBus is a proprietary communications protocol for home and building automation that can handle cable lengths up to 1000 metres using Cat.5 cable.
It was created by the ‘Clipsal Integrated Systems’ division for use with its brand of home automation and building lighting control system.
It can be used in the control of 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, CBus 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 CBus far more suitable for large, commercial applications.

The CBus System can be used to control lighting and other electrical systems and products via remote control and can also be interfaced to a home security system, Audio/Visual products and other electrical items. The CBus system is available in a wired and wireless version, with a gateway available to allow messages to be sent between wired and wireless networks.

Technical Notes

The wired CBus system uses a standard category 5 UTP (Unshielded Twisted Pair) cable as its network communications cable.
Clipsal manufacture 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 CBus. Outside of distribution panels standard category 5 UTP cable can be used.

The category 5 CBus network wiring uses a free topology architecture.

The maximum number of CBus networks in one installation is 255 (note that this limitation does not apply if a CBus 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 CBus unit requires 18mA @ 15-36Vdc to operate. However some CBus units require up to 40mA.
More than one CBus power supply can be connected to a CBus network to provide sufficient power to the CBus units, the CBus power supplies will share the load evenly.
Each CBus network requires a network burden. This network burden can be enabled on CBus output units through software or a hardware burden can be connected to the network.
Each CBus network requires at least one system clock generating unit for data synchronisation.
The isolation between the mains supply circuitry and the 36V dc CBus circuitry is greater than 3.5kV. This is achieved using double wound transformers and opto isolators. This means the CBus wiring, connections and circuitry can be considered Extra Low Voltage.

Examples

Clipsal CBus products can be used in many ways but to give you an idea of their scope and flexibility, here are some examples:

HOME THEATRE:
Dim the lights, close the curtains and start the movie all via a remote control.

WELCOME HOME:
Step out of your car and activate hallway, kitchen and family room lights, as well as heating or cooling and your favourite music.

MUSIC THROUGHOUT YOUR HOME:
Enjoy your favourite music anywhere in your home. Your kids can even plug in their MP3 players and listen to music in their rooms.

APPLIANCES:
Turn on the coffee machine from the bedroom with a remote control.

TIMERS, DIMMERS AND SENSORS:
Reduce your electricity costs by using dimmers and lights that turn off when you leave the room or as natural light levels change.

OUTDOOR WATERING AND LIGHTING:
Turn on spa or pool pumps, garden sprinklers and outside garden lights by remote control.

NIGHT-LIGHTS:
Create a night time scene that dims the lights to a low level to avoid glare, or a night-light for children’s bedside lamps.

GOODBYE:
At the push of a button you can turn off all the lights in the house and arm the alarm system.

With Clipsal’s new Wiser system, all of this control can now be done from effectively any device.
Clipsal’s new CBus Wiser Home Control makes technology in your home easyby providing seamless control of music, home cinema, air-conditioning, lighting, sprinkler systems, curtains and shutters, security systems… you name it.
You get the same look and feel for everything, any time, anywhere; from a light switch, a touch screen, a home computer, or even from your flat screen TV, as you’re about to watch a movie.
You can turn on your air-conditioner from your mobile phone on the way home, or check that everything is turned off over the Internet when you get to work.