KNX : Wire based home automation standard

KNX, origin of the word is Konnex from Latin dictionary means connection. KNX is the globally standardized wire line system for the residential & non residential building automation, and have successfully replaced the 75% of predecessor market. It has replaced EIB (European International Bus), EHS (European Home System) & Baitbus which was use mainly in France.

Being stable wire system, KNX have become the first globally recognized standard systems approved by various standards as below

United States of America ANSI / ASHRAE 135

European Union EN 500900

China GB / T 20965

International ISO / IEC 14543 - 3

CEN EN 13321 - 1

It is hardware independent standard, and all the KNX products from any manufacturer can be operate with one another without failure. All the KNX devices & data protocols are compliant with the KNX standards hence upward & downward compatibility is possible thereby making same as future proof. Hence KNX devices are inter-operable and Net-workable. As the KNX devices are capable to be connected with all the components in the network, the transparency as well as utilization of information across the network is possible. The availability for single cable bus for the integration for different systems helps in designing the seamless solution.

The physical communication Medias as per KNX standards are

Twisted pair wiring, Power line networking, Radio (KNX-RF), Infrared, Ethernet.

The main components for KNX are

Sensors, Actuators and components generally referred as SAC . Sensors gather the information about the subject & object, and transmit same as data telegrams. While as actuators receive these data telegrams for action. And the components included application for connectivity on the bus. The topologies supported are tree, line & star while as ring topology is not permitted.

KNX logical topology in figures is as below

Devices on fully distributed line        65,536

Address space                     16 bit

Devices/ Line                               256

Total lines                                 15

Line coupler                                1

Segments per line                           4

Devices per segment                       64

Segment Length                               1000 Meters

Connections with segments             4

Length in total for 256 Devices         4000 Meters

The twisted pair transmission using KNX standards are mathematically as below

Signalling speed             9600 bit/sec

Wave resistance 120 Ohms at 100 KHz

Line resistance Min: 20 Ω/km, Max 75 Ω/km.

Maximum capacitance bus-to-bus line max 800 pF/m at 800 Hz.

Network nodes               57600

MAC control length 1000 Meters

Total segments 4

Maximum length 4000 Meters

The modes of configuration are A, E & S means Automatic, Easy & System mode respectively. In Automatic mode devices are generally plug & play, in Easy mode little knowledge is require while-as in System mode high expertise is needed for design and installation.

KNX is widely used in building & home automation like Lighting, Blinds & Shutters, Security Systems, Energy Management, HVAC Systems, Monitoring Systems, Remote Control, Metering, Audio& Video systems etc.

KNX Association administers the KNX standards worldwide

For updates & latest articles, visit https://www.connectedbynet.com follow at twitter, facebook, linkedin & for any discussion contact [email protected]