Modifiers and Operators in IL

Table 5. Modifiers

Modifier	Combined with operator	Description
`C`	`JMP`, `CAL`, `RET`	The command is executed only when the result of the preceding expression is `TRUE`.
`N`	`JMPC`, `CALC`, `RETC`	The command is executed only when the result of the preceding expression is `FALSE`.
`N`	Otherwise	Negation of the operand (not of the accumulator)

Table 6. Operators with the possible modifiers

Operator	N	Meaning	Example
`LD`	`N`	Loads the (negated) the value of the operand into the accumulator	`LD ivar`
`ST`	`N`	Stores the (negated) contents of the accumulator in the operand	`ST iErg`
`S`		Sets the operand (type `BOOL`) to `TRUE` if the contents of the accumulator is `TRUE`	`S bVar1`
`R`		Sets the operand (type `BOOL`) to `FALSE` if the contents of the accumulator is `TRUE`	`R bVar1`
`AND`	`N,(`	Bitwise `AND` of the accumulator value and (negated) operand	`AND bVar2`
`OR`	`N,(`	Bitwise OR of the accumulator value and (negated) operand	`OR xVar`
`XOR`	`N,(`	Bitwise exclusive OR of the accumulator value and (negated) operand	`XOR N,(bVar1,bVar2)`
`NOT`		Bitwise negation of the accumulator value
`ADD`	`(`	Addition of the accumulator value and the operand The result is written to the accumulator.	`ADD ivar1`
`SUB`	`(`	Subtraction of the operand from the accumulator value The result is written to the accumulator.	`SUB iVar2`
`MUL`	`(`	Multiplication of accumulator value and operand The result is written to the accumulator.	`MUL ivar2`
`DIV`	`(`	Addition of the accumulator value and the operand The result is written to the accumulator.	`DIV 44`
`GT`	`(`	Checks if the accumulator value is greater than the operand value The result (`BOOL`) is written to the accumulator.	`GT 23`
`GE`	`(`	Checks if the accumulator value is greater than or equal to the operand value The result (`BOOL`) is written to the accumulator.	`GE iVar2`
`EQ`	`(`	Checks if the accumulator value is equal to the operand value The result (`BOOL`) is written to the accumulator.	`EQ iVar2`
`NE`	`(`	Checks if the accumulator value is not equal to the operand value The result (`BOOL`) is written to the accumulator.	`NE iVar1`
`LE`	`(`	Checks if the accumulator value is less than or equal to the operand value The result (`BOOL`) is written to the accumulator.	`LE 5`
`LT`	`(`	Check if the accumulator value is less than the operand value The result (BOOL) is written to the accumulator.	`LT cVar1`
`JMP`	`CN`	Unconditional (conditional) jump to the specified jump label	`JMPN next`
`CAL`	`CN`	(Conditional) call of a program or a function block (if the accumulator value is TRUE)	`CAL prog1`
`RET`		Exit the box and return to the calling box	`RET`
`RET`	`C`	If the accumulator value is `TRUE`: Exit the box and return to the calling box	`RETC`
`RET`	`CN`	If the accumulator value is `FALSE`: Exit the box and return to the calling box	`RETCN`
`)`		Evaluation of the reset operation

Example 9. Example

Application	Description	Examples
Multiple operands for one operator	. Options You enter the operands into consecutive rows, separated by commas in the 2nd column. You repeat the operator in consecutive rows.	Variant 1: Variant 2:
Complex operands	For a complex operand, you enter the opening bracket `(` in the first column. You enter the closing bracket in the first column in a separate row following the operand entries of the following rows.	A string is rotated by one character each cycle.
Function block call, program call	Column 1: `CAL` operator or `CALC` operator Column 2: Name of the function block instance or program and opening bracket `(` If no parameters follow, then the closing bracket `)` is entered here. Rows to follow that: Column 1: Parameter name followed by `:=` for input parameter or `=>` for output parameter Column 2: Parameter value followed by a comma `,` if further parameters follow The closing bracket `)` is input after the last parameter. As a limitation according to the IEC standard, complex expressions cannot be used here. You need to assign such constructs to the function block or the program before the call.
Function call	Line 1: Column 1: `LD` Column 2: Input variable Line 2: Column 1: Function name Column 2: Further input parameters separated by comma CODESYS writes the return value into the accumulator. Line 3: Column 1: `ST` Column 2: Variable into which the return value is written
Action call	Like function block call or program call. The action name is appended to the name of the FB instance or the program.
Jump	Column 1: `JMP` operator or `JMPC` operator Column 2: Name of the jump label of the destination network In the case of an unconditional jump, the preceding instruction sequence must end with one of the following commands: `ST`,`STN`, `S`, `R`, `CAL`, `RET`, `JMP` In the case of a conditional jump the execution of the jump depends on the loaded value.

. For more information, see the following: