Summa Series Servodrive Product Manual
EtherCAT Communications
Document Version: V1.01
(Dec, 2019)
© 2019 ESTUN Automation Co., Ltd. All right reserved.
5-4
5.3.3
EtherCAT State Machine
The EtherCAT state machine is used to manage the communications states between the master and slave
applications when EtherCAT communications are started and during operation, as shown in Figure 5-2.
Normally, the state changes for requests from the master.
Figure 5-2
EtherCAT state machine
Init
Pre-Operational
Safe-Operational
Operational
(OI)
(IP)
(PI)
(OP)
(PS)
(SP)
(SO) (OS)
(SI)
Power ON
Table 5-1 lists the state transition and initialization process.
Table 5-1
Description of state or transition
State or Transition
Operation
Init (I)
Mailbox communications are not available.
Process data communications are not available.
Init to Pre-
Operational (IP)
The master sets the DL address and Sync Manager Channels for mailbox
communications.
The master initializes DC clock synchronization.
The master requests the Pre-Operational state.
The master sets the AL control register.
The slaves check whether the mailbox was initialized correctly.
Pre-Operational (P)
Mailbox communications are available.
Process data communications are not available.
Pre-Operational to
Safe-Operational
(PS)
The master sets the Sync Manager Channels and FMMU channels for
process data.
The master uses SDOs to set the PDO mappings and the Sync Manager
PDO Assignment parameters.
The master requests the Safe-Operational state.
The slaves check whether the Sync Manager channels for process data
communications and, if required, the distributed clock settings are correct.
Safe-Operational (S)
Process data communications are possible. However, only the input data is
available. The output data is still unavailable.
Safe-Operational to
Operational (SO)
The master sends available output data.
The master requests the Operational state.
Operational (O)
Process data communications are available.
