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User's Guide
A.4 Using the SFC editor
The SFC language is used to describe operations of a sequential process. It uses a
simple graphic representation for the different steps of a process, and conditions
that enable the change of active steps. A SFC program is entered by using the
ISaGRAF graphic SFC editor. SFC is the core of the IEC 1131-3 standard. The
other languages usually describe the actions within the steps and the logical
conditions for the transitions. The ISaGRAF graphic SFC editor allows the user to
enter complete SFC programs. It combines graphic and text editing capabilities,
thus allowing the entry of both the SFC chart, and the corresponding actions and
conditions.
A.4.1 SFC language main topics
The SFC language is used to represent sequential processes. It divides the process
cycle into a number of well-defined successive steps (self-contained situations),
separated by transitions. Refer to the ISaGRAF Languages Reference Manual for
more details on the SFC language.
Oriented lines join SFC components. The default orientation of a line is up to down.
These are the basic graphic components used to build a SFC chart:
......................Initial step
......................Step
......................Transition
......................Jump to a step
......................Macro step
......................Macro beginning step
......................Macro ending step
The SFC programming is usually separated into two different levels: The Level 1
shows the graphic chart, reference numbers of the steps and the transitions, and
comments attached to the steps and the transitions. The Level 2 is the ST or IL
programming of the actions within the steps, or the conditions attached to the
transitions. Actions or conditions may refer to sub-programs written in other
languages (FBD, LD, ST or IL). Below is an example of level 1 and level 2
programming:
ICS Triplex ISaGRAF Inc.
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