The Range of MEAN WELL KNX Power Supplies and Products
MEAN WELL first released the highly cost effective KNX-20E-640 back in 2017. Its high level of reliability has made it a firm favourite amongst building automation designers and installers in Australia.
MEAN WELL has since gone on to add other KNX devices to their product line up.
Why KNX?
There are two factors driving the demand for KNX based automation in buildings.
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Energy efficiency
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User comfort and convenience
Globally politicians are grappling with how to reduce carbon emissions. On one side of the ledger is the method of electricity generation, and on the other reducing the rate of energy consumption.
KNX enables a high level of control to reduce energy consumption in residential and commercial buildings.
Artificial lighting and air conditioning are desirable in buildings to provide residents or workers a comfortable and safe environment. By using a KNX intelligent control system the associated energy consumption can be reduced significantly, whilst retaining the desired level of comfort.
Before the introduction of KNX, building control systems tended to be complicated in terms of electrical wiring, because each type of device needed its own physical control cable as shown in the following diagram:
Designing and installing such a system was time consuming and expensive, prohibiting its implementation in many projects. Not to mention the additional fire risk that would needed to have been managed because of the high density of cabling.
The advantage of the KNX system is that it is a two-wire bus routed installation, transmitting the signals between devices in parallel along the 240 VAC mains wiring.
This substantially reduces the amount of wiring required to install a building automation system. Of course, this reduces the cost of installation and ongoing maintenance.
MEAN WELL Power Supply for KNX Bus
The MEAN WELL KNX-20E-640 was the very first KNX device that MEAN WELL introduced.
The beauty of KNX is that it is suitable for both straight forward installations, and highly complex projects.
Regardless of the type of installation a dedicated KNX power supply is needed to power the KNX Bus.
A standard switch mode power supply cannot be used for this purpose.
To explain why this is the case let’s look at a simple window blind control application. If you simply connected the control button to the motorised blind nothing would happen. The bus is not powered, so no command can be transmitted from the control button to the motor.
If you installed a standard switch mode power supply the button could transmit its control signal. However, because the power supply cannot generate a complete and proper signal the blind system's actuator is unable to receive or respond to the control signal.
A KNX Power supply with an integrated choke needs to be used. When the button transmits the active pulse signal onto the Bus, the KNX Power supply will immediately respond with an equalisation pulse due to the integrated choke.
The active and equalisation pulse is then combined to generate a correct KNX signal representing “0” in the digital world. The combined waveform is finished within 104 µsec, which is equivalent to 10 kHz. This is followed with another combined waveform for “0”, or no waveform (just 30 Vdc) for “1” in the next 104 µsec.
This “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 can now operate properly.
Other KNX devices, such as lighting, heating, HVAC, security...etc., work on the same principle, which means only one bus is required, allowing for a high level of design flexibility.
Each KNX device consumes 10mA from the power supply when transmitting and receiving a signal on the bus. The KNX power supply is rated 640mA, allowing up to 64 devices to be controlled on one KNX bus.
MEAN WELL KNX Power Supply with 1280mA Output
ADM also stocks the MEAN WELL KNX-40E-1280 KNX bus power supply.
The KNX-40E-1280 gives customers the same high reliability, whilst remaining remarkably cost effective. The higher output current allows you to power more KNX devices on a line segment.
KNX is fast growing in popularity as a building automation communications protocol.
Prior to the introduction of KNX, each device would need its own separate communications and electrical wiring. This made the installation of sophisticated building automation systems expensive and meant that greater attention to fire risk management was needed, due to the high density of wiring.
KNX uses the 24VDC wiring to transmit power and signal to each device on the bus, with the 240VAC mains wiring only being used to power the higher powered gear, such as motors for blinds.
This makes the installation of such systems far more cost effective and greatly reduces the amount of additional wiring required.
One noticeable feature of the KNX-40E-1280 is its compact size. It is only 4 SUs (72mm) wide, compared to the 6 SU width you would normally associate with other KNX power supplies with a similar power output. So, it won’t take up more real estate then necessary in the distribution board.
The MEAN WELL KNX-40E-1280 comes with a 3-year manufacturer’s warranty.
MEAN WELL KAA-4R4V Dimming / Lighting Control Actuator
The MEAN WELL KAA-4R4V KNX actuator converts the commands received from sensors, automatic control switches or timers into actions, and forms the interface between the KNX system and electrical devices such as lighting, window blinds and HVAC units.
The MEAN WELL actuator uses high quality mechanical relays, as shown in the below picture to turn ON or OFF any type of loads connected to it.
A good quality relay is key to ensuring high reliability for switching actuators used in a KNX building automation system.
MEAN WELL uses relays that meet the EN60669-1 standard. This standard applies to switches for household and similar fixed electrical installations. MEAN WELL carries out rigorous testing to ensure their products exceed the requirements of this standard.
Size Does Matter
All KNX devices including the KNX power supply, input devices, and actuators are usually installed in a distribution board within the building.
In the image below you can see a typical distribution board. The dimensions of the MEAN WELL’s KNX devices have been designed according to the standard DIN 43880. This ensures installation uniformity.
The width of the KNX device is denoted by one or multiple standard units (SU). By definition, each single SU should not be more than 18 mm wide.
Typically, a 640mA KNX Power supply will be 4 SU wide, in other words 54mmwide. Whereas a 1280mA KNX Power supply will be 6 SU (108mm) wide or more.
The MEAN WELL KNX-20E-640 power supply is only 3 SU wide!
This allows more room for other KNX devices to be accommodated in the distribution board.
Conclusion
KNX systems offer many benefits to owners and managers of modern residential and commercial buildings. A KNX power supply is required to run the KNX system smoothly.
MEAN WELL offers a 640mA KNX Bus power supply, which is only 3 SU wide!
The MEAN WELL KNX actuator incorporates high quality mechanical relays. It is a well-designed KNX actuator, which meets the corresponding standards to ensure long and stable operation with minimised maintenance and service.
The MEAN WELL KAA-4R4V multi-channel actuator offers 16A or 10A in a compact 4 SU housing. All units are tested and certified, with test reports provided.
With over 35 years of industrial power supply experience, you can trust MEAN WELL KNX products to provide you with a reliable and safe solution for your KNX system.
If you would like any further information on MEAN well products, please contact ADM on 1300 236 467. A member of our expert team will gladly answer any questions that you may have.
