Library namespace

Syntax:

<Bibliotheksnamensraum>.<Bibliotheksbausteinbezeichner>

Sample: Lib_A.FB_Sample

A library function block identifier is extended with the library namespace (prefixed with a dot as separator) to access the library function block in an unambiguous and qualified manner. Usually the namespace and the name of a library are the same.

Sample:

A library is integrated in a project and contains a function block FB_Sample. However, a function block with the same name is already instantiated locally in the project. Use Lib_A.FB_Sample as the name for the library block, in order to access the library block, rather than the local function block.

VAR
    fbSample    := FB_Sample;         // Instantiation of the project function block FB_Sample
    fbSampleLib := Lib_A.FB_Sample;   // Instantiation of the library function block FB_Sample
END_VAR

You can define a different identifier for the namespace. To this end, in your capacity as library developer enter a namespace in the project information when you create a library project. Alternatively, you can specify a special namespace when you create a PLC project in the library manager for a library in the Properties view.

For more information, see: Using libraries

Operator # for direct access

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

It is possible for local components of global variable lists, structures or function blocks to shadow library blocks with the same name, thus causing ambiguity. As a result, access with the usual namespace convention is not possible. In this case, use the operator # to force direct access.

Syntax:

<Namensraum>#<Pfad zum Bibliotheksbaustein>

Sample

Global variable list with the name "Tc2_Standard"

{attribute 'qualified_only'}
VAR_GLOBAL
    Concat : INT;
END_VAR

Use of the Concat variable from the global variable list and the CONCAT library function from Tc2_Standard

PROGRAM MAIN
VAR
    fbTon : Tc2_Standard#TON;
    nVar  : INT;
    sVar  : STRING;
END_VAR

// Access to the global variable Concat
Tc2_Standard.Concat := nVar;

// Access to the library function CONCAT
Tc2_Standard#CONCAT('Test','1');