Product : ISaGRAF V3
Date : 5-March-1996
File : Sfcintic.SFC modeling in downloaded data base (TIC code).htm
Subject : SFC modeling in downloaded data base (TIC code)
Keywords: SFC - TIC - SFC engine
This document gives more explanation about the format of the ISaGRAF
downloaded code, and refers to the reference guide of the ISaGRAF
data base and TIC code.
TIC code format is sometimes complex because it presumes that the
target includes an SFC algorythm.
Note that, there is a compiler option (uncheck "use SFC engine")
that translates the SFC chart into ST instructions.
If "Use SFC engine" is checked, the TIC code (classical three address
binary code) is completed by SFC chart description in the
ISaGRAF downloaded code. Below are the main entry points to
understand all this:
- The application is made of cyclic programs (always run), functions
(sub routines called by other programs), and SFC charts.
- To each program or function correspond one linear list of TIC
instructions. Such a list is called a "sequence" in the reference
- To each SFC transition corresponds one TIC sequence, which is the
evaluation of the boolean condition attached to the transition.
- To each SFC step correspond three TIC sequences, corresponding to
actions which are executed:
1: when the step becomes active,
2: while the step is active,
3: when the step becomes inactive.
These three sequences are called "begin", "complex" and "end" in the
data base description document.
One SFC program is coded as a list of steps and transitions (first
part ADR_SEQ) and the attached TIC sequences (second part ADR_CODE).
On the first part, each step is described as a structure with three
pointers to TIC code sequences (for actions) ; each transition is
described as a structure with one pointer to the TIC code sequence
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