Allen-Bradley Micro800 General Instructions Manual page 17

Calling a function
Connected Components Workbench
When a function of the Functions section is called by itself or one of its called
functions, a run-time error occurs. Furthermore, functions do not store the local
values of their local variables. Since functions are not instantiated, they cannot call
function blocks.
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A function can be called by a program, by a function, or by a function block.
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Any program of any section can call one or more functions. A function can
have local variables.
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A function has no instance meaning local data is not stored and so is usually
lost from one call to the other.
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Because the execution of a function is driven by its parent program, the
execution of the parent program is suspended until the function ends.
Main program Function
Defining function and parameter names
The interface of a function must be explicitly defined with a type and a unique
name for each of its calling (input) parameters or return (output) parameters. A
function has one return parameter. The value of a return parameter for a function
block is different for each programming language (FBD, LD, ST).
Function names and function parameter names can use up to 128 characters.
Function parameter names can begin with a letter or an underscore followed by
letters, numbers, and single underscores.
Rockwell Automation Publication 2080-RM001D-EN-E - February 2015
Finding information about instructions and ladder elements
TM does not support recursive function calls.
Function
Chapter 1
17