5   EtherCAT Communications
5 - 6
AC Servomotors/Servo Drives 1S-series with Built-in EtherCAT® Communications User’s Manual (I586)
5-3 EtherCAT State Machine
The EtherCAT State Machine (ESM) of the EtherCAT slave is controlled by the EtherCAT master.
 
Note The Bootstrap mode is not supported.
State
SDO 
communications
PDO 
reception
PDO 
transmission
Description
Init Not possible Not possible Not possible Communication initialization is in 
progress. Communications are not 
possible.
Pre-Operational Possible Not possible Not possible Only SDO communications are pos-
sible in this state. This state is 
entered after initialization is com-
pleted. In this state, the network set-
tings are initialized.
Safe-Operational Possible Not possible Possible In this state, PDO transmissions are 
possible in addition to SDO commu-
nications. PDO transmissions can be 
used to send information such as sta-
tus from the Servo Drive.
Operational Possible Possible Possible This is a normal operating state. 
PDO communications can be used to 
control the Servomotor.
Safe-Operational
Pre-Operational
Initialization
Operational