5-4
5-3 EtherCAT State Machine
OMNUC G5-series AC Servomotors and Servo Drives User’s Manual (with Built-in EtherCAT Communications)
5
EtherCAT Communications
5-3 EtherCAT State Machine
The EtherCAT State Machine (ESM) of the EtherCAT slave is controlled by the EtherCAT
Master.
Safe-Operational
Pre-Operational
Init
Operational
State
SDO com-
munica-
tions
PDO re-
ception
PDO
transmis-
sion
Description
Init Not
possible.
Not
possible.
Not
possible.
Communications are being initialized.
Communications are not possible.
Pre-Operational
(Pre-Op)
Possible.
Not
possible.
Not
possible.
Only mailbox communications are possible
in this state. This state is entered after
initialization has been completed. It is used
to initialize network settings.
Safe-Operational
(Safe-Op)
Possible.
Not
possible.
Possible.
In this state, PDO transmissions are
possible in addition to mailbox
communications. DC mode cyclic
communications can be used to send
information such as status from the Servo
Drive.
Operational (Op)
Possible. Possible. Possible.
This is a normal operating state. DC mode
cyclic communications can be used to
control the motor.