The KNX protocol is developed from the merger of the three major European bus protocols EIB, BatiBus and EHS. Based on EIB, it takes into account the physical layer specifications of BatiBus and EHS, and absorbs the advantages of configuration modes in BatiBus and EHS. The complete solution for building automation.

The KNX Association was established in 1999. The KNX Association is an international organization that promotes KNX technology and standards around the world. established. Basically, the world's electrical manufacturers have KNX products. Compared to other protocols, KNX is an open international standard in the field of home and building control. Under the use of a debugging software platform, the products of various manufacturers can be compatible with each other, so in terms of standard promotion, the KNX standard has been approved as:

European Standards (CENELEC EN 50090 & CEN EN 13321-1)

International Standard (ISO/IEC 14543-3)

American Standard (ANSI/ASHRAE 135)

Chinese Standard (GB/T 20965-2013)

The KNX system can be widely used in building automation because of its good system advantages:

1. The system structure is a distributed bus structure. The sensors and drivers in the system have independent CPUs, and they are in a peer-to-peer relationship with each other. Damage to any sensor and driver in the system will not affect the operation of other system components that are not associated with the program. When repairing, replacing or upgrading the components and software in the system, the rest of the system can operate as usual, and maintenance is convenient.

2. The system has strong expansibility. For the increase of functions or the increase of control loops, it is only necessary to connect the corresponding components without changing the original components and wiring in the system to meet the requirements.

3. The control loop of the system is a bus system, with a simple structure, without the laying of a large number of bus cables and complicated control design. The driver and system components are installed in the strong electric box. Only one KNX bus is needed to connect the field sensors (smart panels, mobile sensors, etc.) and the equipment in the strong electric box. The bus adopts a 29V power supply mode for data power supply, which is safe, reliable and easy to operate.

4. The modification of the control function is convenient and flexible, only a small amount of program adjustment is required, and it can be realized without rewiring on site. In addition, energy can be saved and efficiency can be improved through effective control methods.

5. All drivers and system components are modular products, using standard 35mm guide rail installation, and the installation size conforms to the specifications of ordinary standard lighting distribution boxes. On-site smart panels and motion sensors are wall-mounted in GB 86 boxes or VDE German standard 80 bottom boxes, which are easy to construct and more convenient to change control functions.

6. The KNX system adopts a layered structure and is divided into branch lines and areas. Under normal circumstances, there can be 15 branch lines connected to the trunk line through the line coupler to form an area. The signal in the branch line can be allowed to enter the trunk line after filtering out unnecessary signals through the line coupler, so as to improve the efficiency of the trunk line communication. The branch lines can also be connected by IP routers, and the trunk line adopts the data transmission method of the local area network, which effectively improves the data exchange rate of the whole system. The data transmission rate in the local area network is determined by the performance of the network equipment.

7. Electrical characteristics:

(1) The bus cable itself has shielding ability, and the bus cable cannot be grounded;

(2) The switch driver with current detection function can monitor whether the circuit electrical equipment is damaged and alarm.

(3) The system component inspection function can monitor whether the components in the system are online. If there is a bus fault or component fault or disconnection, it can be reported in time.