The SFC language is a state diagram. Graphical steps are used to represent stable states, and transitions describe the conditions and events that lead to a change of state. Using SFC highly simplifies the programming of sequential operations as it saves a lot of variables and tests just for maintaining the program context.
Important note
| You must not use SFC as a decision diagram. Using a step as a point of decision and transitions as conditions in an algorithm should never appear in a SFC chart. Using SFC as a decision language leads to poor performance and complicate charts. ST must be preferred when programming a decision algorithm that has no sense in term of "program state". |
Below are basic components of an SFC chart:
| Chart: |
Programming: |
| Steps and initial steps Transitions and divergences Parallel branches Macro-steps Jump to a step |
Actions within a step Timeout on a step Programming a transition condition |
The workbench fully supports SFC programming with several hierarchical levels of charts: i.e. a chart that controls another chart. Working with a hierarchy of SFC charts is an easy and powerful way for managing complex sequences and saves performances at run time. Refer to the following sections for further details:
Defining a hierarchy of SFC
programs
How to control a SFC child