UDFB instances
Like other instruction blocks in
FactoryTalk Design Workbench
, user-defined function blocks (UDFB) are available from Toolbox
.To use a UDFB in a program, create an instance of the UDFB by calling it in your program. Each instance has its unique copy of the UDFB instance data that consists of the internal member variables and all of its input and output parameters. When a UDFB is called for a given instance, the UDFB logic operates on that instance's copy of data. The values of the instance data are retained from one execution of the UDFB to the next.
When multiple instances are created in a program:
- For ladder diagram programs, the instance name is user-defined, depending on the name of the variable that is assigned to the UDFB.
- For function block diagram and structured text programs, the instance name is given by default, incrementing by one for each instance.
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