KNX (standard)

KNX (standard)

KNX is a standardised (EN 50090,ISO/IEC 14543), OSI-based network communications protocol for intelligent buildings. KNX is the successor to, and convergence of, three previous standards: the European Home Systems Protocol (EHS), BatiBUS, and the European Installation Bus (EIB). The KNX standard is administered by the Konnex Association.

The standard is based on the communication stack of EIB but enlarged with the physical layers, configuration modes and application experience of BatiBUS and EHS.

KNX defines several physical communication media:

* Twisted pair wiring (inherited from the BatiBUS and EIB Instabus standards)
* Powerline networking (inherited from EIB and EHS - similar to that used by X10)
* Radio
* Infrared
* Ethernet (also known as EIBnet/IP or KNXnet/IP)

KNX is designed to be independent of any particular hardware platform. A KNX Device Network can be controlled by anything from an 8-bit microcontroller to a PC, according to the needs of a particular implementation. The most common form of installation is over twisted pair medium.

KNX is approved as an open standard to:

* International standard (ISO/IEC 14543-3)
* European Standard (CENELEC EN 50090 and CEN EN 13321-1)
* China Guo Biao(GB/Z 20965)

KNX has more than 100 members/manufacturers including:

* ABB
* Bosch
* Miele & Cie KG
* ON Semiconductor
* Schneider Electric Industries S.A.
* Siemens
* Uponor corporation
* Jung

There are three categories of KNX device:

* A-mode or "Automatic mode" devices automatically configure themselves, and are intended to be sold to and installed by the end user.
* E-mode or "Easy mode" devices require basic training to install. Their behaviour is pre-programmed, but has configuration parameters that need to be tailored to the user's requirements.
* S-mode or "System mode" devices are used in the creation of bespoke building automation systems. S-mode devices have no default behaviour, and must be programmed and installed by specialist technicians.