Instruction list

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Instruction List (IL) is one of the 5 languages supported by the IEC 61131-3 standard. It is designed for programmable logic controllers (PLCs). It is a low level language and resembles assembly. All of the languages share IEC61131 Common Elements. The variables and function call are defined by the common elements so different languages can be used in the same program.

Program control (control flow) is achieved by jump instructions and function calls (subroutines with optional parameters).

The file format has now been standardized to XML by PLCopen.

Example[edit]

         LD     Speed
         GT     1000
         JMPCN  VOLTS_OK
         LD     Volts
VOLTS_OK LD     1
         ST     %Q75

Variations[edit]

Siemens PLC instruction list language is known as "Statement List" or "STL" in English, and "Anweisungs-Liste" or "AWL" in German, Italian and Spanish. The user of a Simatic development package may choose between German and International mnemonics to represent instructions. For example "A" for "AND" or "U" for "UND", "I" for "Input" or "E" for "Eingang".

See also[edit]