Omron CJ1W- ECT21, Operation Manual

Page: 84 / 154

4 EtherCAT Communications
4 - 4 CJ-series EtherCAT Slave Units Operation Manual (W541)
4-3 Transitions of Communications
States
The state transition model for communications control of the EtherCAT Slave Unit is controlled by the
EtherCAT master.
The following figure shows the communications state transitions from when the power supply is turned
ON.
Status
SDO
communications
Sending
PDOs
Receiving
PDOs
Description
Init Not possible Not possible Not possible Communications are being initial-
ized. Communications are not possi-
ble.
Pre-Operational Possible Not possible 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
network settings.
Safe-Opera-
tional Possible Possible Not possible In this state, both SDO communica-
tions (message communications) and
sending PDOs are possible.
Information, such as status, is sent
from the EtherCAT Slave Unit.
Operational Possible Possible Possible This is the normal state for communi-
cations.
PDO communications are used to
control the I/O data.
Init
Pre-Operational
Safe-Operational
Operational
Power supply ON