6 IL, SFC and ST programming methods
6.1 Instruction lists
This chapter continues from the previous chapter and discusses the other IEC 1131-3 (International Electrotechnical Commission) programming languages, i.e. instruction lists (IL), sequential function charts (SFC), and structured text (ST).
A programming method, which can be considered to be the entering of a ladder program using text, is instruction lists (IL). Instruction list gives programs which consist of a series of instructions, each instruction being on a new line. An instruction consists of an operator followed by one of more operands, i.e. the subjects of the operator. In terms of ladder diagrams an operator may be regarded as a ladder element. Each instruction may either use ...