Basics communication
EL6751
35
Version: 3.5
In
Pre-Op
state mailbox communication is possible, but not process data communication. The EtherCAT
master initializes the sync manager channels for process data (from sync manager channel 2), the FMMU
channels and, if the slave supports configurable mapping, PDO mapping or the sync manager PDO
assignment. In this state the settings for the process data transfer and perhaps terminal-specific parameters
that may differ from the default settings are also transferred.
Safe-Operational (Safe-Op)
During transition between
Pre-Op
and
Safe-Op
the EtherCAT slave checks whether the sync manager
channels for process data communication and, if required, the distributed clocks settings are correct. Before
it acknowledges the change of state, the EtherCAT slave copies current input data into the associated DP-
RAM areas of the EtherCAT slave controller (ECSC).
In
Safe-Op
state mailbox and process data communication is possible, although the slave keeps its outputs
in a safe state, while the input data are updated cyclically.
Outputs in SAFEOP state
The default set
monitoring sets the outputs of the module in a safe state - de-
pending on the settings in SAFEOP and OP - e.g. in OFF state. If this is prevented by deactivation
of the watchdog monitoring in the module, the outputs can be switched or set also in the SAFEOP
state.
Operational (Op)
Before the EtherCAT master switches the EtherCAT slave from
Safe-Op
to
Op
it must transfer valid output
data.
In the
Op
state the slave copies the output data of the masters to its outputs. Process data and mailbox
communication is possible.
Boot
In the
Boot
state the slave firmware can be updated. The
Boot
state can only be reached via the
Init
state.
In the
Boot
state mailbox communication via the
file access over EtherCAT
(FoE) protocol is possible, but no
other mailbox communication and no process data communication.
4.3
General notes for setting the watchdog
ELxxxx terminals are equipped with a safety feature (watchdog) that switches off the outputs after a
specifiable time e.g. in the event of an interruption of the process data traffic, depending on the device and
settings, e.g. in OFF state.
The EtherCAT slave controller (ESC) in the EL2xxx terminals features 2 watchdogs:
• SM watchdog (default: 100 ms)
• PDI watchdog (default: 100 ms)
SM watchdog (SyncManager Watchdog)
The SyncManager watchdog is reset after each successful EtherCAT process data communication with the
terminal. If no EtherCAT process data communication takes place with the terminal for longer than the set
and activated SM watchdog time, e.g. in the event of a line interruption, the watchdog is triggered and the
outputs are set to FALSE. The OP state of the terminal is unaffected. The watchdog is only reset after a
successful EtherCAT process data access. Set the monitoring time as described below.
The SyncManager watchdog monitors correct and timely process data communication with the ESC from the
EtherCAT side.
