Networks: EtherCAT industrial Ethernet protocol for motion control, Power over Ethernet
Austin, TX – EtherCAT, an industrial Ethernet fieldbus, continues to make strides in motion control. Forty vendors have readily available or publicly announced high-performance EtherCAT servo drives, says the EtherCAT Technology Group (ETG) . In related news, the ETG governing organization for that Ethernet protocol enhanced specifications to allow use of IEEE 802.3af Power over Ethernet (PoE).
The support from drive vendors indicates that EtherCAT has a leading role in motion control. No other Industrial Ethernet technology is represented by such a variety of products from so many vendors. A new multi-vendor demo with servo drives from several companies networked with one EtherCAT system took place at the 2008 SPS/IPC/Drives show in Nuremberg, Germany, last week. The booth featured more than 170 EtherCAT products from 59 vendors.
Featuring performance paired with cost efficiency and topology flexibility, EtherCAT offers distributed clock mechanisms and supports precise drive synchronization without special hardware in master devices. Many motion control vendors use EtherCAT as a system bus. Since it was developedherCAT servo drives.
In other news, ETG has expanded its namesake technology with a new Power over EtherCAT enhancement that uses IEEE 802.3af 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 enhancement was finalized at the fall meeting of the ETG Technical Committees near Frankfurt, Germany. Stub lines and star topology, plus line, tree and redundant ring have been among the EtherCAT topology options. It is now possible to design EtherCAT devices with just one connector each powered over the data line. The Power over Ethernet standard IEEE802.3af supports up to 13 W per device. In EtherCAT slave devices, ETG specifies mode A of the standard, which only needs four wires; standard Industrial Ethernet connectors such as the 4-pin M12 can still be used. Devices powered by a separate line can connect to Power over EtherCAT breakouts. It is possible to enhance the spec towards future high-power IEEE802.3at standard (PoE Plus or High Power PoE), which is downward-compatible.
Also read: Industrial Ethernet applications in real time .
See other articles in the System Integration Monthly eNewsletter .