1 Features and System Configuration
1 - 4
CJ-series EtherCAT Slave Units Operation Manual (W541)
SDO communications is used to perform message communications.
Whenever necessary, the EtherCAT master sends a command to a slave, and then the slave returns a
response to the EtherCAT master.
The following data communications can be performed.
• Reading and writing process data
• Setting slaves
• Monitoring slave status
Mailbox Communications (SDO Communications)
EtherCAT master
Slave
Ethernet frame
Slave
Slave
Slave
Logical process data
CRC
Data a
Data b
Data c
Ethernet
header
Ether
CAT
header
1st EtherCAT
datagram
2nd EtherCAT
datagram
3rd EtherCAT
datagram