Ethercat Overview; Ethercat Technology; Device Profiles - WEG CFW11 User Manual

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ETHERCAT OVERVIEW

Following it is presented general information about the EtherCAT tecnology.
2.1

ETHERCAT TECHNOLOGY

EtherCAT (Ethernet for Control Automation Technology) is a Real Time Ethernet technology introduced originally in
2003 by Beckhoff. In 2007, it was integrated into the international fieldbus standards IEC 61158. The EtherCAT
Technology Group (ETG) promotes EtherCAT and is responsible for its continued development.
EtherCAT communication technology is based on 100BASE-TX Ethernet physical layer. An EtherCAT bus consists
of a master system and up to 65535 slave devices, connected together with standard Ethernet cabling.
In order to improve network performance, instead of sending one Ethernet package at a time to each node, EtherCAT
network takes a different approach, employing "on the fly" processing hardware. The frame, containing data to several
slaves, is initially sent by the master to the first slave on the network. The slave device process the incoming Ethernet
frames directly, extract or insert relevant data and transfer the frame to the next EtherCAT slave device, without
waiting the entire frame to be received. The last slave device in the bus segment sends the fully processed frame
back, so that it is returned by the first slave to the master as a kind of response frame, which maximize the use of
the full duplex Ethernet bandwidth. This approach makes data update between master and slaves really fast and
deterministic, ideal for application fields like machine controls.
2.2 DEVICE PROFILES
The EtherCAT communication allows different protocols to be used in the application layer. For frequency inverter
CFW11, the CANopen over EtherCAT (CoE) device profile is available, where the CANopen protocol is applied to
EtherCAT. Different communication objects available to CANopen are also used via EtherCAT, like Service Data
Objects (SDO), Process Data Objects (PDO) and the Object Dictionary structure to manage the parameters.
EtherCAT Overview
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