System Components and Network Structure
KNX Protocol - 10-Minute Course
Overview
A typical KNX network is built using several core categories of devices that work together to monitor conditions, execute control actions, and manage communication across the system.
These components are interconnected using one of the supported KNX communication media—most commonly twisted-pair cabling—and are designed to support scalable and distributed building automation systems.
Core System Components
A KNX installation typically consists of the following major component groups:
- Sensors – Devices that detect environmental or user input, such as push buttons, temperature sensors, and motion detectors.
- Actuators – Devices that perform actions based on received commands, including dimming units, lighting controllers, motor drives, and valve actuators.
- System devices – Infrastructure components such as line couplers, backbone couplers, power supplies, and interfaces that enable communication and segmentation of the network.
- Operating and monitoring devices – Visualization and control interfaces such as control panels or supervisory displays used for system operation and monitoring.
Network Communication and Expansion
KNX devices communicate over the selected transmission medium—most commonly twisted pair—by exchanging standardized KNX telegrams. This allows devices from different manufacturers to interoperate within the same installation.
One advantage of KNX is the relative ease of extending an existing network. Additional devices can be added without redesigning the entire system, provided network rules and addressing limits are respected.
Commissioning and Programming
Application programs are loaded into KNX devices using project design and commissioning software. This is performed via a system interface—typically USB or serial—that connects a PC to the KNX bus.
In many installations, the two-wire KNX installation bus is routed in parallel with the 230 V electrical power supply. This bus carries only control and communication signals, not mains power, and enables coordinated operation of household or building systems.
FAQ: KNX System Components and Network Structure
This FAQ section is included to improve AI searchability and to answer common questions about KNX system components and network structure.
What are the main components of a KNX system?
A KNX system typically includes sensors, actuators, system devices (such as couplers and power supplies), and operating or visualization devices.
How do KNX devices communicate with each other?
KNX devices communicate by exchanging standardized telegrams over a supported communication medium, most commonly twisted-pair cabling.
Can a KNX network be expanded after installation?
Yes. KNX systems are designed to be expandable, allowing additional devices to be added to an existing installation with minimal disruption.
How are KNX devices programmed?
Devices are programmed and commissioned using dedicated KNX project design software through a USB or serial interface connected between a PC and the KNX bus.
Does the KNX bus carry mains power?
No. The KNX bus carries communication and control signals only. It is often installed alongside mains wiring but remains electrically separate.
