Lenze DDS v2.3 - Manual (Page 49)

Drive PLC Developer Studio
Programming languages
4-11
l
DDS EN 2.3
4.4 Sequential Function Chart (SFC)
Sequential Function Chart is a graphically oriented language that enables the user to describe the
chronological sequence of different actions within a program.
Example of a network in SFC
4.4.1 Step
An organization unit written in SFC consists of a sequence of steps that are interconnected through
transitions.
There are two different step types:
•
The simplified step consist of an action and a flag to indicate whether the step is active or
not. A small triangle appears in the top right-hand corner of the step to indicate that the
action for a step has been implemented.
•
An IEC step consists of a flag and one or more assigned actions or Boolean variables. The
associated actions appear to the right of the step.
4.4.2 Action
An action may contain a sequence of instructions in IL, CFC or ST, a number of networks in FBD or
LD or another sequence structure (SFC).
•
Simplified steps always have an action linked to the step.
•
Actions can be edited by double-clicking the step linked to the action or selecting the step
before executing menu command Extras
➞ ➞ ➞ ➞Zoom action/transition. Furthermore, the
configuration allows one entry and / or one exit action per step.
•
In the Object Organizer, actions of IEC steps are grouped directly underneath their SFC
organization unit and can be loaded into the editor with a double-click or pressing the
<Enter> key. New actions can be generated with Project
➞ ➞ ➞ ➞Add action.
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