PLC programming language of IEC standard (IEC61131–3) 5 programming language:
1) sequential function chart (Sequential function chart);
2) ladder (Ladder Diagram);
3), function block diagram (Function block diagram);
4) list of instructions (Instruction list);
5) structured text (Structured text).
Sequential function chart (SFC), ladder diagram (LD), function block diagram (FBD) is a graphical programming language, instruction list (IL), and structured text (ST) is a written language.
There have been more and more production of PLC manufacturers provide products comply with IEC6113l–3 standard, manufacturers introduced running on the PC “soft PLC“ package is designed according to IEC6113l–3 standard.