EtherCAT state machine transition (ESM)

ESM State machine

Four state machines should be supported
●Init.
Pre-Operational.
Safe-Operational.
Operational.

An optional state machine
●Bootstrap.

Its state transformation relationship , As shown in the figure below ：

State transformation	Local management services
IP	Start email communication
PI	Stop mailbox communication
PS	Start entering updates
SP	Stop inputting updates
SO	Start output update
OS	Stop output update
OP	Stop output update , Stop inputting updates
SI	Stop output update , Stop mailbox communication
OI	Stop output update , Stop inputting updates , Stop mailbox communication
IB	Start boot mode
BI	Restart the device

1)Init
“Init” The state defines the initial point of the communication relationship between the master station and the slave station on the application layer . On the application layer , There is no direct communication between master station and slave station . The master station uses “Init” State to initialize a group ESC Configuration register . If the slave station supports mailbox service , Then the corresponding synchronization manager configuration is also “Init” Status complete .
2)Pre-Operational
If the slave supports optional mailboxes , It's in “Pre-Operational” Status mailbox is activated . Both master and slave stations can exchange application specific initialization information and parameters using mailboxes and appropriate protocols . In this state, there is no process data communication .
3)Safe-Operational
stay “Safe-Operational” state , The slave application should transmit the actual input data without processing the output data . Output should be set to “ Safe state ”.
4)Operational
stay “Operational” state , The slave application shall transmit the actual input data and the master application shall transmit the actual output data .
5)Bootstrap
In optional “Bootstrap” state , The slave application should be able to accept passing FoE New firmware downloaded by agreement .

summary ：

When the state machine transitions from Init To Operational The state needs to be changed down level by level . But from Operational To Init Can convert directly .