Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 740)

L-force | PLC Designer
General Editors
738 DMS 4.1 EN 03/2011 TD29
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Symbol Element name / Example Description
Abb. 410 IEC-extending step actions
The "Step active", "Step Entry" and "Step
Exit" actions are defined in the step
properties.
2. IEC-extending step actions:
These are actions extending the IEC standard,
previously known as "3S step actions": The
actions must be available as objects below the
SFC object. The action names must be unique.
- "step entry" action:
This type of step action will be processed as soon
as the step has become active and before the
"step active" action.
The action is associated to a step via an entry in
the "step entry" field of the step properties. It is
represented by an "E" in the lower left corner of
the respective step box.
- "step active" action:
This type of step action will be processed when
the step has become active and after a possible
"step entry" action of this step has been
processed. However in contrast to an IEC step
action (see above) it is not executed once more
when it gets deactivated and it cannot get
assigned qualifiers.
The action is associated to a step via an entry in
the "step active" field of the step properties. It is
represented by a small triangle in the upper right
corner of the respective step box.
- "step exit" action:
An exit action will be executed once when the
step has got deactivated. Notice however that
this execution will not be done in the same, but
at the beginning of the subsequent cycle.
The action is associated to a step via an entry in
the "step exit" field of the step properties. It is
represented by an "X" in the lower right corner of
the respective step box.
A sequential function chart can diverge, that is
the processing line can be branched into two or
several further lines ("branches"). Parallel
branches will be processed parallel (both at a
time), in case of alternative branches only one
will be processed depending on the preceding
transition condition. Each branching within a
chart is preceded by a horizontal double (parallel)
or simple (alternative) line and also terminated by
such a line or by a jump.