Lenze E94AYCET - Manual (Page 57)

Lenze · E94AYCET communication module (EtherCAT®) · Communication Manual · DMS 9.0 EN · 02/2014 · TD17
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7 Data transfer
7.3 EtherCAT state machine
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7.3 EtherCAT state machine
Before communication is possible via EtherCAT, the fieldbus passes through the EtherCAT state
machine during start-up. The following illustration depicts the possible state changes from the
point of view of an EtherCAT slave:
[7-1] EtherCAT state machine
The current status of the EtherCAT state machine is shown in C13861 / C14861 and is indicated via
the RUN LED.
E94AYCET009
Operational
Pre-Operational
Init
Safe-Operational
State Description
Init • Initialisation phase
• No SDO/PDO communication with the slaves
• Device detection possible by means of a fieldbus scan
Pre-operational • The fieldbus is active.
• SDO communication (mailbox communication) is possible.
• No PDO communication
Safe-operational • SDO communication (mailbox communication) is possible.
• PDO communication:
• The input data in the process image are updated.
• The output data from the process image are not transferred to the slaves.
Operational Normal operation:
• SDO communication
• PDO communication
• Fieldbus synchronisation successful (if used)
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Note!
• A fieldbus scan can be carried out during any EtherCAT status.
• SDO communication via the EtherCAT bus is only possible if at least the "Pre-
Operational" state has been reached.
• Only in the transitional phases between states can bus nodes be in different states.