/logic/iec code changes... (IEC 61131-3 translator section)

  • Thread starter Campbell, David (Ex AS17)
  • Start date

Thread Starter

Campbell, David (Ex AS17)

An explanation of recent changes to /logic/iec directory:

1) iec.y (the bison source file) has been moved to master.y
2) a small program to strip "C" style comments out of files has been added
3) Makefile modified to generate iec.y from master.y

The changes were made to allow work on a smaller section of the IEC 61131-3 specifications. The entire bison source is approximately 60 printed pages of code (2473 lines) which makes reviewing the code difficult (I prefer to go through a
paper copy with a highlight pen an mark areas needing work). By stripping the commented sections out the size drops to 20 pages (10 pages after using ATP to format for 2 pages per page).

Hopefully by the weekend I should have functions/function blocks working with "Structured Text" (ST), then I can move onto
"Instruction List" (IL).

Some help with the IL would be appreciated, specific problems include nesting of IL statements and dealing with mixed data types.
Strongly recommend having a read of the IEC standard (the draft is around on the net somewhere) before looking at the code.

I have updated the FAQ with a link to an old draft of the IEC standard, please note that I do not have any control over the remote FTP site
so the draft could easily disappear without any warning.

David Campbell

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