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Z-wave

Building and home automationsystems can be wired systems or systems that use the low voltage network. With Z-Wave, developed by the Danish-American company Zensys, there is a wireless platform for building automation based on radio technology. Z-Wave supports all building automation functions: lighting and room lighting, climate and ventilation, security and alarm techniques, reading techniques and device controls.

The development of Z-Wave

One of the development goals of Z-Wave was to create the most cost-effective technology possible that is easy to install, self-configuring, and does not require special network management. The Z-Wave network is such a self-configuring mesh network that ensures error-free communication and reconfigures itself with self-healing mechanisms in case of failure.

Z-Wave as a mesh network

Z-Wave configuration with connected control units

Z-Wave configuration with connected control units

The Z-Wave wireless network can be configured as a meshed network because a source routing protocol operates at the link layer. Each node of the meshed network can transmit, receive and forward data. Since Z-Wave nodes can be powered by the mains voltage or by a battery, be permanently connected or mobile, they have to perform a wide variety of functionalities. They therefore act as slave or portable controller nodes, as routers, bridges or static controller nodes.

Another development goal was to create nodes that consume as little power as possible. The battery-powered nodes should be able to operate for 10 years and more with one set of batteries. To achieve this goal, certain nodes are in energy-saving sleep mode from which they are periodically woken up and send their data and any configuration changes to the corresponding controller node.

Z-Wave module with HW and SW platform, photo: Zensys

Z-Wave module with HW and SW platform, photo: Zensys

In order to manufacture Z-Wave nodes at low cost, a highly integrated hardware/software platform has been developed with its own microprocessor, memory, radio interface and software. This component can be easily integrated with sensors and actuators from a wide range of manufacturers.

In order to meet the various applications in home automation, the Z-Wave Alliance has specified 30 device classes that cover all major areas of home automation and must be interoperable with each other.

Specifications of Z-Wave

Specifications of Z-Wave

Z-Wave is a two-way RF system with a data rate of 9.6 kbps to 100 kbps. It operates with frequency shift ke ying (FSK) in the ISM band at 868.42 MHz, and in the U.S. at 908.42 MHz because these frequencies propagate better indoors than 433 MHz or 2.4 GHz. The 868 MHz band is largely regulated and is therefore suitable for the transmission of time-critical control signals.

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Englisch: Z-wave
Updated at: 20.10.2015
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