Transitions Of Communications States - Omron CJ1W-ECT21 Operation Manual

4 EtherCAT Communications
4-3 Transitions of Communications
States
The state transition model for communications control of the EtherCAT Slave Units is controlled by the
EtherCAT master.
The following figure shows the communications state transitions from when the power supply is turned
ON.
Status
Init
Pre-Operational
Safe-Operational
Operational
4 - 4
Power supply ON
Init
Pre-Operational
Safe-Operational
Operational
SDO Sending
communications PDOs
Not possible Not possible Not possible
Possible Not possible Not possible
Possible Possible
Possible Possible
CJ-series EtherCAT Slave Units Operation Manual for NJ-series CPU Unit (W542)
Receiving
PDOs
Communications are being initialized.
Communications are not possible.
Only SDO communications (message
communications) are possible in this
state.
This state is entered after initialization is
completed. It is used to initialize net-
work settings.
Not possible In this state, both SDO communications
(message communications) and send-
ing PDOs are possible.
Information, such as status, is sent from
the EtherCAT Slave Unit.
Possible This is the normal state for communica-
tions.
PDO communications are used to con-
trol the I/O data.
Description