Operator: __VARINFO

The operator is an extension of the IEC 61131-3 standard.

The operator yields information about a variable. You can save the information as data structure in a variable of data type __SYSTEM.VAR_INFO.

Syntax in the declaration

<name of the info variable> : __SYSTEM.VAR_INFO; // Data structure for info variable

Syntax for calls

<name of the info variable> := __VARINFO( <variable name> ); // Call of the operator

Example 154. Example

FUNCTION_BLOCK FB_Velocity
VAR_INPUT
        rVelocity: REAL := 1.2;
END_VAR
VAR_OUTPUT
END_VAR
VAR
        infoVelocity: __SYSTEM.VAR_INFO; //Info of Velocity
END_VAR

infoVelocity := __VARINFO(rVelocity); // Gets the info of Velocity locally

PROGRAM PLC_PRG
VAR
        iCounter : INT := 0; // Counts the calls
        infoCounter : __SYSTEM.VAR_INFO; //Info of Counter
        arrA : ARRAY [1..2, 1..2, 1..2] OF INT := [0, 1, 2, 3, 4, 5, 6, 7]; // Stores the A data
        infoA : __SYSTEM.VAR_INFO; //Info of A
        fbVel : FB_Velocity;
END_VAR

iCounter := iCounter + 1;
infoCounter := __VARINFO(iCounter);
infoA := __VARINFO(arrA);
fbVel();

The iCounter and arrA variables are recognized in the application code. The variable information is saved in the infoCounter and infoA variables. Moreover, the FB_Velocity function block is instantiated.

Data Type: __SYSTEM.VAR_INFO

Name	Data Type	Initialization	Description
`ByteAddress`	`DWORD`	0	Address of the variable Example: `16#072E35EC` Note: For bit access of a variable `<variable name>.<bit index>`, the address of the variable which contains the bit is given.
`ByteOffset`	`DWORD`	0	Offset of the variable address (in bytes) Example: `13936` bytes Note: If the variable is global, then the offset is relative to the beginning of the area. If the variable is a local variable in a function or method, then the offset is relative to the current stack frame. If the variable is a local variable in a function block, then the offset is relative to the function block instance.
`Area`	`DINT`	0	Memory area number `Area` in the runtime system Example: `-1` Means that the variable is not global in the memory, but relative to an instance or on the stack Note: The memory areas are device-dependent.
`BitNr`	`INT`	0	Number of bits (in bytes) Example: `16#00FF` bytes Note: If the variable is not an integer data type, then: `BitNr = -1 = 16#FFFF`
`BitSize`	`INT`	0	Memory size of the variable (in bits) Example: `16` bits
`BitAddress`	`UDINT`	0	Bit address of the variable Requirement: The variable is located in the input memory area `I`, output memory area `Q`, or marker memory area `M`. Otherwise the value is undefined.
`TypeClass`	`TYPE_CLASS`	`TYPE_BOOL`	Data type class of the variable Example: `TYPE_INT`, `TYPE_ARRAY` Note: For user-defined data types or function block instances, `TYPE_USERDEF` is output as the data type class.
`TypeName`	`STRING(79)`	‚‘	Date type name of the variable as `STRING(79)` Note: For user-defined data types, the function block name or the DUT name is output. Example: `'INT'`, `'ARRAY'`
`NumElements`	`UDINT`	0	Number of array elements Requirement: The variable has the data type `ARRAY`. Example: `8`
`BaseTypeClass`	`TYPE_CLASS`	`TYPE_BOOL`	Elementary basic data type of the array elements Requirement: The variable has the data type `ARRAY`. Example: `TYPE_INT` for `arrA : ARRAY [1..2,1..2,1..2] OF INT;`
`ElemBitSize`	`UDINT`	0	Memory size of the array element (in bits) Requirement: The variable has the data type `ARRAY`. Example: `16` bits for `arrA : ARRAY [1..2,1..2,1..2] OF INT;`
`MemoryArea`	`MEMORY_AREA`	`MEM_MEMORY`	Information about the memory area `MEM_GLOBAL`: Global memory area Example: in `Area 0` `MEM_LOCAL`: Local memory area in `Area -1` `MEM_MEMORY`: Marker memory area `%M` Example: in `16#10` in `Area 1` `MEM_INPUT`: Input memory area `%I` Example: in `16#04` in `Area 2` `MEM_OUTPUT`: Output memory area `%Q` Example: in `16#08` in `Area 3` `MEM_RETAIN`: Retain memory area Example: in `16#20` in `Area 0` Example: `MEM_GLOBAL` Note: The memory area configuration is device-dependent.
`Symbol`	`STRING(39)`	‚‘	Variable name as `STRING(39)` Example: `'iCounter'`, `'arrA'`
`Comment`	`STRING(79)`	‚‘	Comment of the variable declaration Example: `'Counts the calls'` or `'Stores the A data'`