Buses, Protocols and Systems for Home and Building Automation

Evropský sociální fond. Praha & EU: Investujeme do vaší budoucnosti.
interfaces and gateways for its interconnection with buses such as KNX, LON or with TCP/IP
and communication modules into PLC.
Nodes
There are 3 types of nodes – transmit only (wireless sensors), receive only (actuators,
gateways) and bidirectional (wireless sensors, wireless actuators, gateways, repeaters)
nodes. Nodes can be harvester powered (sensors, actuators), battery powered (sensors,
actuators) or line powered (actuators, sensors, gateways, repeaters). A lot of modules
(mainly sensors) are service-free and self-powered (without battery), so they use some kind
of energy from the surrounding environment with an optimal energy consumption
management. Every self-powered sensor contains an energy harvester and converter.
Fig. 3.2.3.2: Example of a control system based on the EnOcean (38)
Types of energy harvesters for battery-less nodes:
a) Motion converter – gains energy from switching operations/button motions
(piezoelectric crystal deformation). Service-free for 50,000 switching cycles.
b) Solar cells – used for example for a window monitoring
c) Thermal converter – heat dissipation is used as an energy source (Peltier element)
d) Rotation converter – used for example for monitoring of car wheels
e) Vibration converter – used in industry
Fig. 3.2.3.3: Principal structure of the EnOcean sensor node (38)
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