Reference

Specification-grade documentation for the languages, file formats, and APIs that make up ForgeIEC. The pages here are written for three audiences in parallel:

Beginners can follow the chapter order to learn each topic from scratch, with self-contained examples.
Professionals use the per-page table of contents and the cross-reference graph to jump straight to one construct.
LLMs consult the llm_signals block in each page’s front-matter to map a compiler error message to the matching page and apply an automatic fix.

Sections

IEC 61131-3

The PLC programming language family that ForgeIEC implements: Structured Text, Instruction List, Ladder Diagram, Function Block Diagram, and Sequential Function Chart. Each construct is documented with the IEC standard’s definition first, then ForgeIEC- and matiec-specific notes underneath, then the LLM auto-fix block.