1.3 Classification of EtherCAT Communication
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1.3 Classification of EtherCAT Communication
EtherCAT provides the following two communication functions.
( 1 ) Process Data Communication Function
This is equivalent to cyclic (I/O) communication. An EtherCAT system has a 4-gigabyte logical process data area
(cyclic data area).
Mapping the logical process data area at the EtherCAT master station to each of the slave nodes enables cyclic (I/O)
communications between the master and slave stations.
( 2 ) Mailbox Communication Function
This is equivalent to message communication.
The EtherCAT master station sends commands to the slave stations, and the slave stations return a response to the mas-
ter station.
• Reading from/writing to the system (EtherCAT system) register
• Reading/writing process data
• Reading from/writing to user memory
