IEC 61131-3
IEC 61131-3 international standard for PLC programming according to uniform rules
I/O
I/O in-/output of a function block diagram
Instance
Instance copy of a type. By the instance you reserve memory space for the structure of the type and define the instance name.
Instant-Reload
Instant-Reload: allows online-modifications for the running code.
Instruction list (IL)
Instruction list (IL) a widespread Assembler-like programming language for PLC-systems