The demand for comfort and versatility in either residence or commercial building is growing fast in recent years. It implies a complex system covering intelligent control, low energy consumption, high level security should be involved. In the past, the system is quite complicated in terms of electrical wiring because each function of device needs its own physical control cable. It requires a large amount of effort in terms of design and installation at the beginning and later deploy the high difficulty on maintenance. The high density of cables could also have a high risk of fire. Therefore, a new installation for uni-communication between any controller, sensor and actuator are developed and named with KNX system. The KNX system uses only two-wire installation bus routed transmitting the signals between devices in parallel to the 230 VAC mains wire. Therefore, KNX system substantially reduces the mass work of electrical wirings inside the building and further lower fire risk and maintenance.
The KNX Power Supply KNX-20E-640 is a 640mA power supply with high efficiency and a small footprint of only 3SU (52.5 mm). The device has a KNX bus choke output and an additional output for ancillary power. The -30~+70°C wide temperature operating range can meet all kinds of applications. With over 30 years of industrial power supply experience, KNX-20E-640 is engineered to be a reliable and safe solution for KNX bus environment.
The KNX system can not only be very simple with few devices but also be extended a complex system with hundreds of devices for use in a building. A KNX power supply is essential for the KNX Bus environment and it cannot be replaced with conventional switching mode power supply. Imagine a simple system with only two devices (wall flush button and actuator for controlling electrical blind) on the KNX Bus. When a user presses the button in order to turn on the electrical blind and see through the window, it turns out the digital command from the button cannot be transmitted to the actuator because the KNX Bus is not powered. If a 30 Vdc conventional power supply gets added into the existing Bus, the button could transmit the signal onto the bus. However, the actuator is still not able to receive and further response. But if a KNX Power supply with integrated choke is added into system, it will response with an equalization pulse immediately when the button transmits the active pulse signal onto the Bus. The active and equalization pulse is then combined to realize a correct signal representing “0” in the digital world. The combined waveform should be finished within 104 µsec which is equivalent 10 kHz following with another combined waveform for “0” or no waveform (just 30 Vdc) for “1” in the next 104 µsec. Such “0” & ”1” sequential numbering represent the actual function/command from the button to the targeted actuator of the blind system. As result, this simple KNX system is operating properly.
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