The EtherCAT Technology Group (ETG), Nuremberg, Germany, has expanded its namesake technology with a Power-over-EtherCAT enhancement. This specification makes use of IEEE802.3af Power-over-Ethernet (PoE) functionality and can be implemented with commercially available chips. Power over EtherCAT is suitable for encoders or linear position sensors, which can now be designed to connect to EtherCAT and powered using a single standard Ethernet cable.
The Power-over-EtherCAT enhancement was finalized at the fall meeting of the ETG Technical Committees. Stub lines and star topology, together with line, tree and redundant ring, have always been among the EtherCAT topology options. This flexibility is now enhanced with the possibility to design EtherCAT devices with just one connector each that are powered over the data line.
PoE standard IEEE802.3af supports up to 13 W per device. For EtherCAT slave devices, the ETG specifies mode A of the standard, which only needs four wires; standard industrial Ethernet connectors can still be used. Devices powered by a separate line can be connected to Power-over-EtherCAT breakouts. It also is possible to enhance the spec toward the future high-power IEEE802.3at standard (PoE Plus or High-Power PoE) because this is downward compatible.