Ethercat State Machine (Esm); Communication Status - Mitsubishi Electric MELSERVO-J4 Instruction Manual

1. EtherCAT COMMUNICATION

1.4 EtherCAT State Machine (ESM)

The communication status of MR-J4-_TM_ servo amplifiers is classified and managed by EtherCAT State
Machine (ESM) that the EtherCAT standard specifies.

1.4.1 Communication status

The following table shows the classification of the communication status. Two communication types are
provided: One is the PDO (process data object) communication where command data and feedback data
are sent and received at a constant period. Another is the SDO (service data object) communication where
object data is sent and received asynchronously. Refer to chapter 3 for details of the PDO communication.
Refer to chapter 4 for details of the SDO communication.
ESM status
After the power is on, the communication status is the init state. The SDO communication and PDO
Init communication cannot be performed. The master accesses the DL-Information register and initializes
communication.
The SDO communication can be performed. The PDO communication cannot be performed. The initial setting
Pre-Operational
for network and initial transfer of parameters can be performed in this state.
The SDO communication can be performed. Though the PDO communication also can be performed, all
Safe-Operational operations (commands) such as servo motor drive are invalid. When the DC mode is selected, synchronization
is established in this state.
Both the SDO communication and PDO communication can be performed. Commands using the PDO
Operational
communication are valid and the servo motor can be driven.
This is not supported by MR-J4-_TM_ servo amplifiers.
Bootstrap
The mailbox communication with the FoE protocol can be performed. Firmware can be updated through
EtherCAT in this state.
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