Eaton easySafety Manual page 360

Safety function blocks
356
Example - Architecture of Category 4 according to
EN ISO 13849-1
Monitoring of the switch position change of two contactors
with cross-circuit monitoring of the external wiring. The
safety output of an ES01QS emergency-stop function block
switches the EM01 OC coil and activates the function block.
The enable must be removed if the feedback signal for the
contactor switch position is delayed. The monitoring time is
set to 2.5 seconds.
h
Note that the emergency-stop function block is in AST
(Automatic Start) operating mode. Manual enabling is
only possible via the Reset coil of the EM function block. If
the safety application does not have an EM function block,
the emergency-stop function block should be set to MST
or CST mode in order to prevent unwanted enabling after
the emergency-stop actuator is released.
This looks as follows in the electrical circuit diagram:
02/16 MN05013001Z EN