Instruction Lists

Instruction lists (or ILs) are one of the five PLC programming languages defined by the IEC 61131-3 standard. (The others being ladder logic diagrams, function block diagrams, sequential function charts, and structured text.)

ILs are not a graphical programming language. Instead, they most resemble assembly language programming. As the name implies, a program is a series of instructions, listed in much the same way as an assembly program.