Operator '__VARINFO'

This 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 the call:

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

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 that 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 For example in `‎Area 0‎` `‎MEM_LOCAL‎`: Local memory area in `‎Area -1‎` `‎MEM_MEMORY‎`: Marker memory area `‎%M‎` For example in `‎16#10‎` in `‎Area 1‎` `‎MEM_INPUT‎`: Input memory area `‎%I‎` For example in `‎16#04‎` in `‎Area 2‎` `‎MEM_OUTPUT‎`: Output memory area `‎%Q‎` For example in `‎16#08‎` in `‎Area 3‎` `‎MEM_RETAIN‎`: Retain memory area For 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'‎`