KNX стандарты: ғимаратты автоматтандыру жүйесі

Standard in building automation

KNX is an open standard (see EN 50090, ISO/IEC 14543) for commercial and residential building automation. KNX devices can manage lighting, blinds and shutters, HVAC, security systems, energy management, audio video, white goods, displays, remote control, etc. KNX evolved from three earlier standards; the European Home Systems Protocol (EHS), BatiBUS, and the European Installation Bus (EIB or Instabus). It can use twisted pair (in a tree, line or star topology), powerline, RF, or IP links. On this network, the devices form distributed applications and tight interaction is possible. This is implemented via interworking models with standardised datapoint types and objects, modelling logical device channels.

A KNX installation always consists of a set of devices connected to the bus or network. Device models vary according to node roles, capabilities, management features and configuration modes, and are all laid down in the profiles. There are also general purpose device models, such as for bus coupling units (BCUs) or bus interface modules (BIMs). Devices may be identified and subsequently accessed throughout the network either by their individual address, or by their unique serial number, depending on the configuration mode. (Unique serial numbers are allocated by the KNX Association Certification Department.) Devices can also disclose both a manufacturer specific reference and functional (manufacturer independent) information when queried.

A KNX wired network can be formed with tree, line and star topologies, which can be mixed as needed; ring topologies are not supported. A tree topology is recommended for a large installation. KNX can link up to 57,375 devices using 16 bit addresses. The lowest eight bits provide up to 256 addresses within one line, which can consist of up to four segments, each having a maximum of 64 (TP1 64) devices, or up to 256 (TP1 256) devices. Each segment requires a local power supply and the maximum length of a segment is 1000 m. (The actual number of devices supported is dependent on the power supply and the power load of the individual devices.) Segments connected with line repeaters can extend to a length of 4000 m and link up to 256 devices. Lines may be grouped together into an area, with up to 15 lines connected to a main line via line couplers. The next four bits of the address are used to identify individual lines. An entire domain can be formed with 15 areas linked by a backbone line using backbone couplers, and the top four bits of the address space identify an area. (Line repeaters may not be used on a backbone or mainline.) Coupling units allow address filtering which helps to improve performance given the limited bus signal speed. An installation based on KNXnet/IP allows the integration of KNX sub networks via IP as the KNX address structure is similar to an IP address.

The TP1 twisted pair bus (inherited from EIB) provides asynchronous, character oriented data transfer and half duplex bidirectional differential signaling with a signaling speed of 9600 bit/s. Media access control is via CSMA/CA. Every bus user has equal data transmission rights and data is exchanged directly (peer to peer) between bus users. SELV power is distributed via the same pair for low power devices. A deprecated specification, TP0, running at a slower signalling speed of 4800 bit/s, has been retained from the BatiBUS standard but KNX products cannot exchange information with BatiBUS devices.

PL 110 power line transmission is delivered using spread frequency shift keying signalling with asynchronous transmission of data packets and half duplex bi directional communication. It uses the central frequency 110 kHz (CENELEC B band) and has a data rate of 1200 bit/s. It also uses CSMA. KNX Powerline is aimed at smart white goods, but the take up has been low. An alternative variant, PL 132, has a carrier frequency centred on 132.5 kHz (CENELEC C band).

RF enables communication in the 868.3 MHz band for using frequency shift keying with Manchester data encoding.

KNXnet/IP port 3671 has integration solutions for IP enabled media like Ethernet (IEEE 802.2), Bluetooth, WiFi/Wireless LAN (IEEE 802.11), FireWire (IEEE 1394) etc.

KNX Telegrams can be signed or encrypted thanks to the extension of the protocol that was developed starting in 2013, KNX Data Secure for securing telegrams on the traditional KNX media TP and RF and KNX IP Secure for securing KNX telegrams tunnelled via IP. KNX Data Secure became an EN standard (EN 50090 3 4) in 2018, KNX IP Secure an ISO standard (ISO 22510) in 2019.

Any product labeled with the KNX trademark must be certified to conform with the standards (and thus interoperable with other devices) by accredited third party test labs. All products bearing the KNX logo are programmed through a common interface using the vendor independent ETS software.