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

(for receptivity).


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