CEI 61131-3 entitled programmable Automats - Part 3: Computer programming languages defines five Computer programming languages to use for the programmable automats.

• Language Ladder (Diagram with relay)

• Sequential function chart (SFC) near to the language Grafcet
• functional Boxes (FBD), in the form of Diagram
• Text structured (ST)
• List of instructions (IT), a pseudo Assembler

See too

• international electrotechnical Commission
• the official synopsis of the CEI 61131-3 (previsualisation on www.iec.ch)