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TR-Electronic GmbH 2016, All Rights Reserved
09/29/2020
TR-EMO-BA-GB-0022 v03
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4.3 EtherCAT State Machine (ESM)
The Application Management contains the EtherCAT State Machine, which describes
the states and state changes of the slave application. Apart from a few details, the
ESM corresponds to the CANopen Network Management (NMT). In order to enable
reliable starting behavior the "Safe Operational" state has been introduced in
EtherCAT. In this state valid entries are transmitted, while the outputs remain in safe
status.
Figure 3: EtherCAT state machine
Status
Description
IP
Start Mailbox Communication
PI
Stop Mailbox Communication
PS
Start Input Update
SP
Stop Input Update
SO
Start Output Update
OS
Stop Output Update
OP
Stop Output Update, Stop Input Update
SI
Stop Input Update, Stop Mailbox Communication
OI
Stop Output Update, Stop Input Update, Stop Mailbox Communication
Table 3: States, State Machine
