Instruction List (IL) is an assembler type textual programming language.
Instruction List is one of the oldest, textual programming methods for PLCs. Large (and mostly incompatible) sets of instructions have been created by many vendors. The IEC 61131 Instruction list reduced this set to a minimum and favours the usage of functions and function blocks for more complex tasks.
The textual form of the Sequential Function Chart (SFC) can be used within Instruction List to create sequential control.