Power and Data Connectors Simplify Deployment of KNX Factory Automation Networks

Building automation is transitioning from traditional central controllers to distributed automation systems, with intelligence disbursed across all connected devices. This trend is powered by the improvements in artificial intelligence (AI), which provide local intelligence within a building's system components. This allows all building systems, including air conditioning, lighting, and security, as well as sensors and other elements, to more accurately coordinate their functionality and regulate the parameters needed for safe and efficient structural operation.

This coordination requires the transfer of data and power over an efficient and effective interface. Let’s look at how the KNX interface meets building automation requirements and how Phoenix Contact is simplifying the installation of reliable KNX connectors to accelerate deployments.

What is KNX?

KNX is a widely used open building automation standard for residential, commercial, and industrial buildings that enables sensors, actuators, controllers, and power sources to interact peer-to-peer without a central controller. The system's hardware components are certified and comply with the KNX standard, ensuring interoperability. The software element of KNX is a standardized protocol, the Engineering Tool Software (ETS), which allows users to configure devices, addressing, and logic for the automation system.

The advantages and applications of KNX

KNX offers interoperability with devices from hundreds of manufacturers that conform to the standard, enabling flexibility in selecting or replacing components. Its decentralized architecture also offers the advantage of easy scalability. Devices can be added or changed to increase the size of the installation without significant modifications. The interchangeability of certified devices makes repairs and expansion simple and eliminates vendor lock-in.

Decentralization also supports reliability, as a single faulty device cannot bring down the entire system. Only the functions of the defective device are lost.

The applications for KNX are many. For example, lighting systems can switch lights on and off based on time or occupancy, or use dimming and color selection to set a mood. You can use KNX to control building heating, ventilation, and air conditioning systems to maintain a comfortable environment, with temperature and humidity adjustment based on building occupancy and exterior or other area-specific conditions.

A building-wide KNX network can be applied to safety and security. The system can detect intrusion, fire, water leaks, and other breaches. The network's flexibility allows security monitoring based on time of day, occupancy, or alert status.

For interconnections, the KNX network can use twisted pair, powerline, radio frequency (RF), or IP/Ethernet wiring. Twisted pair is the most common wiring choice using low-voltage cable, such as industry-standard J-Y(ST)Y cables.

KNX connector examples

Phoenix Contact has introduced a new series of Print Terminal Spring (PTS 0.5) and Pin Strip Terminal (PST 1.0) pin headers for KNX twisted-pair networks operating at 9.6 kilobits per second (kbits/s). The PTS 0.5 connectors, such as the 1574299 and 1574300 (Figure 1), are free-hanging two-position socket connectors with a 5.75 millimeter (mm) pitch that accept wires with gauges of 18 to 22 AWG or metric sizes of 0.34 to 0.75 mm². This includes J-Y(ST)Y cable with diameters ranging from 0.6 to 0.8 mm.

Figure 1: Shown are examples of PTS 0.5 KNX twisted-pair connectors with a 5.75 mm pitch. (Image source: Phoenix Contact)

The connectors differ in color to meet KNX coding requirements, enabling accurate wire insertion. The 1574299 connectors are gray/yellow, while the 1574300 are red/black. They both offer two contacts each, arranged in a single row with four wire ports per contact. The four ports provide a simple method for continuous loop-through of potentials in bus applications. Note that each contact has a test port for easy probe access.

Dimensionally, these connectors are very compact, measuring 12.45 × 10 × 10 mm.

The mating 1574198 (Figure 2) PST 1.0 plug header is a through-hole-mounted two-position terminal block header that mates with either connector.

Figure 2: The 1574198 PST 1.0 KNX terminal block header for through-hole mounting mates with both the 1574299 and 1574300 connectors. (Image source: Phoenix Contact)

The connector and header devices are easy to assemble (Figure 3).

Figure 3: Shown are the stages of assembly of the KNX connectors and header. (Image source: Phoenix Contact)

Wiring is quick and easy thanks to the tool-free push-in connector contacts and color-coded connector bodies. The push-in connections use a special steel contact spring that opens automatically when the conductor is pushed in, providing the proper force to ensure a reliable, low-resistance electrical connection. The KNX-compatible color-coded connector bodies reduce the probability of wiring errors and speed assembly. Connector attachment to the header is at a right angle.

The assembled connectors are rated to handle up to 6 amperes (A) at voltages reaching 320 volts, with a rated contact resistance of 1.4 milliohms (mΩ).

Conclusion

With advances in AI driving increased connectivity, Phoenix Contact’s design innovation is especially evident in KNX network-based control systems. Its connectors and headers support the future of building automation, enabling reliable, easy-to-deploy connections.