EtherCAT State Machine

EtherCAT state machine

Figure 1: EtherCAT State Machine

Where the transitions are from:

  • Init to Pre-Operational (Pre-Op): Master configures the Sync Manager channels for Mailbox communication.
  • Pre-Op to Safe-Operational (Safe-Op): Master configures parameter using the Mailbox.
  • Safe-Op to Operational (Op): Master sends valid Outputs.

Different States

State Description

Bootstrap
  • Recommended if firmware updates are necessary.
  • No Process Data communication.
  • Communication via Mailbox on Application Layer.
  • Only the File Access over EtherCAT (FoE) protocol is available.

Init
  • No communication on the Application Layer.
  • Master has access to the DL-Information registers.

Operational (Op)

Inputs and Outputs are valid.

Pre-Operational

(Pre-Op)
  • Mailbox communication on the Application Layer.
  • No Process Data communication.

Safe-Operational

(Safe-Op)

  • Mailbox communication on the Application Layer.
  • Process Data communication.
  • Only Inputs are evaluated (Outputs in Safe state).

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