STOBER
9 | Looking for more information about EtherCAT?
02/2020 | ID 443025.06
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9
Looking for more information about EtherCAT?
The following chapters summarize the key terms, services and relationships relating to EtherCAT.
9.1
EtherCAT
EtherCAT (Ethernet for Control Automation Technology) is an industrial Ethernet technology for real-time requirements in
automation technology. EtherCAT is focused on short cycle times, low
EtherCAT was invented by Beckhoff Automation GmbH & Co. KG and is currently supported by the international EtherCAT
Technology Group (ETG) organization. EtherCAT is an open technology standardized in the standard IEC 61158 since 2005.
Master/slave principle and the exchange of data
EtherCAT follows a master/slave principle.
A master sends standard Ethernet frames that pass every slave. The frames are are processed as they pass through. More
specifically, each EtherCAT slave has an EtherCAT slave controller (ESC) integrated into its hardware which takes the receive
data addressed to the respective slave as the message passes by and attaches the slave's transmit data on the fly. This
means any delays are due to the hardware processing time. The last slave in the network sends the frame back to the
master.
The EtherCAT master is the only network node that actively sends frames; the EtherCAT slaves simply pass the frame on.
This principle avoids potential delays and ensures real-time capability. The order of the data does not depend on the
physical order of the slaves in the network.