Syntax

( <pragma> )
<scope> ( <type qualifier> )
    <identifier> (AT <address> ) : <data type> := <initial value>;
END_VAR

<pragma>	Repeated optional (never, once, or multiple times) Pragma A pragma is a compiler statement (for example to achieve optimizations such as memory requirements or runtime improvements).	⮫ “Using Pragmas ” ⮫ “Pragmas ”, ⮫ Further information
`‎<scope>‎`	Required Scope `‎VAR‎` `‎VAR_CONFIG‎` Note: If variables with incomplete address information are declared in function blocks (for example, `‎AT %I*‎`), then the variables in the variable declaration `‎VAR_CONFIG‎` have to be completely declared. You can access these variables in a local instance only when this is done. `‎VAR_EXTERNAL‎` `‎VAR_GLOBAL‎` `‎VAR_INPUT‎` `‎VAR_INST‎` `‎VAR_IN_OUT‎` `‎VAR_OUTPUT‎` `‎VAR_STAT‎` `‎VAR_TEMP‎`	⮫ “Variable: VAR ” ⮫ “Variable: VAR_CONFIG ” ⮫ “Variable: VAR_EXTERNAL ” ⮫ “Variable: VAR_GLOBAL ” ⮫ “Object: GVL – Global Variable List ” ⮫ “Variable: VAR_INPUT ” ⮫ “Variable: VAR_INST ” ⮫ “Variable: VAR_IN_OUT ” ⮫ “Variable: VAR_OUTPUT ” ⮫ “Variable: VAR_STAT ” ⮫ “Variable: VAR_TEMP ”
`‎<type qualifier>‎`	Optional Type qualifier `‎CONSTANT‎` `‎RETAIN‎` `‎PERSISTENT‎`	⮫ “Variable: CONSTANT ” ⮫ “Variable: RETAIN ” ⮫ “Variable: PERSISTENT ”
`‎<identifier>‎`	Required Identifier, variable name Note: The rules listed in the chapter "Identifier Designation" have to be followed without exception when assigning an identifier. In addition, you will find recommendations for uniform naming.	⮫ “Identifier Designation ”, ⮫ Further information
`‎AT %<address>‎`	Optional The address is made up as follows: <memory area> <optional size prefix> <memory position> The memory area is subdivided into input memory area, output memory area, or flag memory area (I, Q or M). Example Example `‎AT %I* // Incomplete address‎` `‎AT %I7.5‎` `‎AT %IW0‎` `‎AT %QX7.5‎` `‎AT %MD48‎`	⮫ “Configuring Devices and I/O Mapping ”, ⮫ “Linking a device input with an existing project variable ("mapping") ”, ⮫ “Mapping a device input to a recently created project variable ”, ⮫ “Linking a device with a function block instance ”, ⮫ “Changing and fixing an address value in the I/O map ”, ⮫ “Configuration of the I/O variable update ”, ⮫ “Monitoring of variables in the I/O map in online mode ”, ⮫ “Generating implicit variables for the forcing of I/Os ”, ⮫ “I/O mapping in one dialog for multiple devices ” ⮫ “AT Declaration ” ⮫ “Addresses ”
`‎<data type>‎`	Required Data Type `‎<elementary data type>‎` `‎<custom data type>‎` `‎<function block >‎`	⮫ “Data Types ” ⮫ “Object: DUT ” ⮫ “Object: Function Block ”
`‎<initial value>‎`	Optional Initial value; initialization as a literal, variable, or expression	⮫ “Identifier Designation ”, ⮫ Further information ⮫ Constants and literals, ⮫ Constants and literals, ⮫ Constants and literals, ⮫ Constants and literals ⮫ “ST Expressions ”

Example

Global variable list ‎GVL‎

{attribute 'qualified_only'}
{attribute 'linkalways'}
VAR_GLOBAL CONSTANT
        g_ciMAX_A : INT := 100;
        g_ciSPECIAL : INT := g_ciMAX_A - 10;
END_VAR

Configuration variables ‎GVL_CONFIG‎

{attribute 'qualified_only'}
VAR_CONFIG
        // Generated instance path of variable at incomplete address
        PLC_PRG.fbDoItNow.XLOCINPUT AT %I*: BOOL := TRUE;
END_VAR

Function block ‎FB_DoIt‎

METHOD METH_Last : INT
VAR_INPUT
  iVar : INT;
END_VAR
VAR_INST
  iLast : INT := 0;
END_VAR

METH_Last := iLast;
iLast := iVar;

FUNCTION_BLOCK FB_DoIt
VAR_INPUT
    wInput AT %IW0 : WORD; (* Input variable *)
END_VAR
VAR_OUTPUT
    wOutput AT %QW0 : WORD; (* Output variable *)
END_VAR
VAR_IN_OUT
    aData_A : ARRAY[0..1] OF DATA_A; // Formal variable
END_VAR
VAR_EXTERNAL
        GVL.g_ciMAX_A : INT; // Declared in object GVL
END_VAR
VAR_STAT
    iNumberFBCalls : INT;
END_VAR
VAR
        iCounter: INT;
        xLocInput AT %I* : BOOL := TRUE; // VAR_CONFIG
END_VAR

iNumberFBCalls := iNumberFBCalls + 1;

IEC program ‎PLC_PRG‎

PROGRAM PLC_PRG
VAR
        iLoop: INT;
        iTest: INT;
        fbDoItNow : FB_DoIt;
        iTest_200: INT;
        aData_Now : ARRAY[0..1] OF DATA_A := [(iA_1 := 1, iA_2 := 10, dwA_3 := 16#00FF),(iA_1 := 2, iA_2 := 20, dwA_3 := 16#FF00)];
END_VAR

iTest := GVL.g_ciMAX_A;
iTest_200 :=  2 * GVL.g_ciMAX_A;
fbDoItNow(aData_A := aData_Now);
FOR iLoop := 0 TO GVL.g_ciSPECIAL DO
        ;
END_FOR