Call Functions or Function Blocks

When finalized, you can drag-and-drop UDFBs from the library in the (Project) node to a program just like any other function block. A new instance is automatically created.

Figure 1: Create an Instance of UDFB in a Program

• 
  

• • A single data type parameter defined as IN is passed by the calling program to the UDFB and the body UDFB cannot change its value
    
  • A single data type parameter defined as OUT is set in the body UDFB and always actuated in the calling program after the call
    
  • A parameter which is an array or a structure is always declared as IN (visible on the left of the block). Both the calling program and the body of the UDFB can read and write such a parameter

See also:

• Function Call
• Call a Function Block
• Call a Sub-Program