Communications Between An Ethercat Master And Slaves - Omron FH series User Manual

Communications between an EtherCAT Master and Slaves

This section describes the communications modes between the master and slaves for EtherCAT
communications, and the communications modes for EtherCAT Slave Terminals.
Communications Modes for Communications between an EtherCAT Master and Slaves
Free-Run Mode (Not supported on the FH)
In free run mode, the slave processes the I/O (refreshes the I/O data) asynchronously with respect to the
communications cycle of the master.
DC Mode
In DC mode, the slave processes the I/O (i.e., refreshes the I/O data) in synchronization with the
communications cycle of the master. A distributed clock (DC) system whereby the master and slave share
the same clock is used to synchronize EtherCAT communications. Interruptions (Sync0) are generated in the
slaves at precise intervals based on this clock. Each slave executes I/O processing at this precise timing.
Communications Modes for EtherCAT Slave Terminals
The FH-series Vision Sensors support DC Mode. They do not support Free-Run Mode.
Communications Cycle
The communications cycle is determined by the setting for it in the EtherCAT master.
Refer to the NJ-series CPU Unit Built-in EtherCAT Port User's Manual (Cat. No. W505) for the
communications cycles that are supported by the built-in EtherCAT ports on NJ-series CPU Units.
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EtherCAT Connections (FH-1000 series/FH-3000 series only) Vision System FH/FZ5 Series User's Manual
for Communications Settings (Z342)