Low Cost KNX Power Supply from Mean Well

Your KNX Power Supply doesn't have to be expensive. The MEAN WELL KNX power supply is very cost effective, yet highly reliable!

KNX is a only global standard for home and building control. It is being used more and more all over the world to transmit control data to all building management components and ensure that all components communicate via one common language.

The whole purpose of KNX is to enhance the management of residential and commercial complexes, making them safer, more convenient and more environmentally sustainable. KNX reduces the excessive amount of wiring that is sometimes used to capture data from intelligent sensor and detector devices. As well as making the installation easier and more cost effective, it can also reduce maintenance fees.

The new 20 Watt KNX-20E power supply from MEAN WELL has been designed to power a standard KNX system and MEAN WELL is fast becoming the power supply of choice in the industry. One of the main reasons for this is that it is remarkably cost effective. 

KNX Power Supply

A KNX system can be very simple with just a few devices, but also be an extended, complex system with hundreds of devices throughout a building. In both cases, a KNX power supply is needed for powering the KNX Bus.

All the devices used in a KNX installation are connected by a bus, allowing them to exchange data. KNX systems require a dedicated KNX power supply.

The types of equipment you are likely to see being controlled by a KNX based system includes blinds, lighting, entertainment systems, fans, heating/air conditioning, security systems, etc.

A standard switch mode power supply cannot be used in a KNX system.

Let’s consider a simple KNX system, with a wall flush button and actuator to operate a window blind. For the digital command to be relayed from the button to the actuator, the KNX bus needs to be powered.

Three different scenarios are depicted below.

  • The installation with no power to the KNX Bus
  • The installation with a standard power supply providing power to the KNX Bus
  • The installation with a Mean Well KNX power supply providing power to the KNX Bus

KNX Power Supply Schematic Simple Installation

When a standard switch mode power supply is used, the initial signal (the active pulse) would be transmitted, but the actuator wouldn’t be able to receive and transmit subsequent command signals. This is because the signal is not a complete and proper KNX signal.

The MEAN WELL KNX-20E power supply has an integrated choke. When the button transmits the active pulse signal onto the Bus, the KNX Power supply immediately responds with an equalization pulse, due to the integrated choke.

The active and equalisation pulse is then combined to create the correct signal representing “0” in the digital world. The combined waveform should be finished within 104 μsec, which is equivalent 10 kHz followed, with another combined waveform for “0” or no waveform (just 30 Vdc) for “1” in the next 104 μsec. Such “0” & ”1” sequential numbering represents the actual function/command from the button to the targeted actuator of the blind system. As result, this simple KNX system now operates properly.

The MEAN WELL KNX-20E power supply gives you a no load power consumption of less than 0.5 Watts, so it is perfect for use in applications where minimal power consumption is required in standby mode. It also features 200ms mains failure back up time to protect against brown outs.

An LED indicator shows normal operation, Bus reset and Bus overload situations.

The MEAN WELL KNX-20E power supply is also remarkably compact at only 52.5mm wide and is backed by a 3-year warranty.

For further information on this, or any other MEAN WELL power supply please do not hesitate to call ADM on 1300 236 467. A member of our expert team will gladly answer any questions that you may have. 

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This blog post was updated on 12th June, 2018

29 June 2018