KNX (standard)
Encyclopedia
KNX is a standard
ized (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 or Instabus
). The KNX standard is administered by the KNX Association.
of EIB but enlarged with the physical layer
s, configuration modes and application experience of BatiBUS and EHS.
KNX defines several physical communication medias:
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:
KNX Association, as of September 2011, had nearly 250 members/manufacturers from 29 countries including:
The complete list can be found here at knx.org
The KNX Association has partnership agreements with more than 30,000 installer companies in 100 countries and more than 60 technical universities as well as over 150 training centres.
using differential signaling
with a signaling speed of 9600 bit/s. Ideal wave resistance at 100 kHz is 120 Ω. Line resistance at 20 Ω/km, max 75 Ω/km. Maximum capacitance bus-to-bus line max 800 pF/m at 800 Hz. Higher capacitance requires proportionally shorter cable length. Bus power with 30 V DC and 25 mA Polarization critical. Devices within same physical segment are addressed with 8-bits Maximum 57600 network nodes.
Media access control
is controlled with the CSMA/CA
method.
Maximum segment length is . 4 segments may be connected with line repeaters to establish a network length of . Loops not allowed.
If the destination type flag (DT) is set the packet will be multicast or broadcast. R2-R0 is decremented for each routing hop, like TTL
in IP. L3-L0 correspond to 1-16 user data bytes.
Source is always a physical address. Destination may be either a physical or group address.
Logical “0” is defined as impulse under the reference level 30 V DC. Logical “1” is lack of the same impulses.
There exist an alternative interface speed at taken over from BatiBUS. But KNX TP-0 products will only operate on the same network. But not be able to exchange information with BatiBUS devices.
This results in devices of different manufacturers and different applications that can be combined to a working installation.
The KNX Association member companies have almost 7000 KNX certified product groups in their catalogues. This wide range of products allow, for example, the integration of:
On top of that you can enable access to the system via LAN, analog or mobile phone networks for having a central or distributed control of the system via PCs, Touch screens and Smartphones.
Standardization
Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....
ized (EN 50090
EN 50090
EN 50090 is a standard containing technical rules for Home and Building Electronic Systems .-Safety aspects:* EN 50090-2-2:1996 : System overview - General technical requirements...
, ISO/IEC 14543), OSI
OSI model
The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
-based network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
communications protocol
Communications protocol
A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...
for intelligent buildings. KNX is the successor to, and convergence of, three previous standards: the European Home Systems Protocol
European Home Systems Protocol
European Home Systems Protocol was aimed at home appliances control and communication using power line communication , developed by the European Home Systems Association ....
(EHS), BatiBUS, and the European Installation Bus (EIB or Instabus
Instabus
Instabus, is a decentralized open system to manage and control electrical devices within a facility. It is developed by Berker, Gira, Jung, Merten and Siemens AG. There are about 200 companies of electrical supplies using this communication protocol. The EIB allows all electrical components to be...
). The KNX standard is administered by the KNX Association.
KNX protocol
The standard is based on the communication stackProtocol stack
The protocol stack is an implementation of a computer networking protocol suite. The terms are often used interchangeably. Strictly speaking, the suite is the definition of the protocols, and the stack is the software implementation of them....
of EIB but enlarged with the physical layer
Physical layer
The physical layer or layer 1 is the first and lowest layer in the seven-layer OSI model of computer networking. The implementation of this layer is often termed PHY....
s, configuration modes and application experience of BatiBUS and EHS.
KNX defines several physical communication medias:
- Twisted pairTwisted pairTwisted pair cabling is a type of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs...
wiring (inherited from the BatiBUS and EIB InstabusInstabusInstabus, is a decentralized open system to manage and control electrical devices within a facility. It is developed by Berker, Gira, Jung, Merten and Siemens AG. There are about 200 companies of electrical supplies using this communication protocol. The EIB allows all electrical components to be...
standards) - PowerlinePower line communicationPower 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...
networking (inherited from EIB and EHSEuropean Home Systems ProtocolEuropean Home Systems Protocol was aimed at home appliances control and communication using power line communication , developed by the European Home Systems Association ....
- similar to that used by X10X10 (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...
) - RadioRadio frequencyRadio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
(KNX-RF) - InfraredConsumer IRConsumer IR, consumer infrared, or CIR, refers to a wide variety of devices employing the infrared electromagnetic spectrum for wireless communications. Most commonly found in television remote controls, infrared ports are equally ubiquitous in consumer electronics, such as PDAs, laptops, and...
- EthernetEthernetEthernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
(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
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
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)
- Canadian standard (CSA-ISO/IEC 14543-3)
- European Standard (CENELEC EN 50090 and CEN EN 13321-1)
- China Guo Biao (GB/Z 20965)
KNX Association, as of September 2011, had nearly 250 members/manufacturers from 29 countries including:
- GIRA
- ABB
- AMX LLC
- Berker GmbH Co. KG
- Bosch Thermotechnik
- Cisco Systems
- Control4 EMEA
- Creston Internacional
- Daikin Industries
- Embedded Automation
- Jung
- Legrand
- Miele & Cie KGMieleMiele is a manufacturer of high-end domestic appliances, commercial equipment and fitted kitchens, based in Gütersloh, Germany. Miele has always been a family-owned and -run company, founded in 1899 by Carl Miele and Reinhard Zinkann.-History:...
- ON SemiconductorON SemiconductorON Semiconductor , is a semiconductors supplier company. Products include power and signal management, logic, discrete and custom devices for automotive, communications, computing, consumer, industrial, LED lighting, medical, military/aerospace and power applications...
- Hager
- Schneider ElectricSchneider ElectricSchneider 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...
Industries S.A. - Somfy
- BoschRobert Bosch GmbHRobert Bosch GmbH is a multinational engineering and electronics company headquartered in Gerlingen, near Stuttgart, Germany. It is the world's largest supplier of automotive components...
- Russound/FMP Inc.
- SiemensSiemensSiemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...
- Toshiba
- Uponor corporation
The complete list can be found here at knx.org
The KNX Association has partnership agreements with more than 30,000 installer companies in 100 countries and more than 60 technical universities as well as over 150 training centres.
Wire transmission
Twisted pairTwisted pair
Twisted pair cabling is a type of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs...
using differential signaling
Differential signaling
Differential signaling is a method of transmitting information electrically by means of two complementary signals sent on two separate wires. The technique can be used for both analog signaling, as in some audio systems, and digital signaling, as in RS-422, RS-485, Ethernet , PCI Express and USB...
with a signaling speed of 9600 bit/s. Ideal wave resistance at 100 kHz is 120 Ω. Line resistance at 20 Ω/km, max 75 Ω/km. Maximum capacitance bus-to-bus line max 800 pF/m at 800 Hz. Higher capacitance requires proportionally shorter cable length. Bus power with 30 V DC and 25 mA Polarization critical. Devices within same physical segment are addressed with 8-bits Maximum 57600 network nodes.
Media access control
Media Access Control
The media access control data communication protocol sub-layer, also known as the medium access control, is a sublayer of the data link layer specified in the seven-layer OSI model , and in the four-layer TCP/IP model...
is controlled with the CSMA/CA
Carrier sense multiple access with collision avoidance
Carrier sense multiple access with collision avoidance , in computer networking, is a wireless network multiple access method in which:*a carrier sensing scheme is used....
method.
Maximum segment length is . 4 segments may be connected with line repeaters to establish a network length of . Loops not allowed.
| # | Field | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
|---|---|---|---|---|---|---|---|---|---|
| 0 | Control R-repeated packet Px-priority |
1 | 0 | R | 1 | P1 | P0 | 0 | 0 |
| 1 | Source address #0 | ||||||||
| 2 | Source address #1 | ||||||||
| 3 | Destination address #0 | ||||||||
| 4 | Destination address #1 | ||||||||
| 5 | Destination type Routing info Length |
DT | R2 | R1 | R0 | L3 | L2 | L1 | L0 |
| 6 | User data 1-16 bytes | ||||||||
| Checksum (S) |
If the destination type flag (DT) is set the packet will be multicast or broadcast. R2-R0 is decremented for each routing hop, like TTL
Time to live
Time to live is a mechanism that limits the lifespan of data in a computer or network. TTL may be implemented as a counter or timestamp attached to or embedded in the data. Once the prescribed event count or timespan has elapsed, data is discarded. In computer networking, TTL prevents a data...
in IP. L3-L0 correspond to 1-16 user data bytes.
Source is always a physical address. Destination may be either a physical or group address.
Logical “0” is defined as impulse under the reference level 30 V DC. Logical “1” is lack of the same impulses.
There exist an alternative interface speed at taken over from BatiBUS. But KNX TP-0 products will only operate on the same network. But not be able to exchange information with BatiBUS devices.
Configuration modes
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 bespokeBespokeBespoke is a term employed in a variety of applications to mean an item custom-made to the buyer's specification...
building automationBuilding automationBuilding automation describes the functionality provided by the control system of a building. A building automation system is an example of a distributed control system...
systems. S-mode devices have no default behaviour, and must be programmed and installed by specialist technicians.
KNX Products
One of the strengths of the KNX system, is that any product labeled with the KNX trademark is not a mere declaration of the manufacturer but is based on conformity testing carried out by KNX accredited third party test labs. During these tests, it is not only checked that the device supports the KNX protocol but that its useful data is coded according to the KNX standardized Data types.This results in devices of different manufacturers and different applications that can be combined to a working installation.
The KNX Association member companies have almost 7000 KNX certified product groups in their catalogues. This wide range of products allow, for example, the integration of:
- Lighting control
- Heating/ventilation & Air Conditioning control
- Shutter/Blind & shading control
- Alarm monitoring
- Energy management & Electricity/Gas/Water metering
- Audio & video distribution
On top of that you can enable access to the system via LAN, analog or mobile phone networks for having a central or distributed control of the system via PCs, Touch screens and Smartphones.
See also
- INSTEONINSTEONInsteon is a system for connecting lighting switches and loads without extra wiring. INSTEON is a dual-band mesh home area networking topology employing AC-power lines and a radio-frequency protocol to communicate with devices...
- EnOceanEnOceanEnOcean is a German wireless, energy harvesting technology used primarily in building automation systems, based in Oberhaching. It is not set out for international, European or national standardization; however, EnOcean GmbH is offering its technology and licenses for the patented features under...
- Intelligent building
- Home automationHome automationHome 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...
- Lighting control systemLighting control systemA lighting control system consists of a device that controls electric lighting and devices, alone or as part of a daylight harvesting system, for a public, commercial, or residential building or property, or the theater...
- OpenThermOpenThermOpenTherm is a protocol used in central heating systems between a central heating boiler and a thermostat or controller. It is a point to point protocol where one device is the master and the other the slave . Multiple devices can be linked by using the Multi Point to Point...
- Smart EnvironmentsSmart EnvironmentsSmart environments is a technological concept that, according to Mark Weiser is "a physical world that is richly and invisibly interwoven with sensors, actuators, displays, and computational elements, embedded seamlessly in the everyday objects of our lives, and connected through a continuous...
- Room automation
- Touch panelTouchscreenA touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens can also sense other passive objects, such as a stylus...
- BacnetBACnetBACnet is a communications protocol for building automation and control networks. It is an ASHRAE, ANSI, and ISO standard protocol....
- LonworksLonWorksLonWorks is a networking platform specifically created to address the needs of control applications. The platform is built on a protocol created by Echelon Corporation for networking devices over media such as twisted pair, powerlines, fiber optics, and RF...
- ModbusModbusModbus is a serial communications protocol published by Modicon in 1979 for use with its programmable logic controllers . Simple and robust, it has since become one of the de facto standard communications protocols in the industry, and it is now amongst the most commonly available means of...