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3 PROGRAM ORGANIZATION UNITS
3.4 Precautions
■When a conversion error occurs in VAR_INPUT, VAR_OUTPUT, or VAR_IN_OUT in a macro
type function block
A program block that is the calling source of the function block or the function block may cause the error. In this case, check
the inputs and outputs of the program block that is the calling source of the function block and the function block.
A conversion error (1) occurs in VAR_OUTPUT in the macro type function block (FbPou)
If no error was found in (1), check the inputs and outputs (2) of the corresponding function block in the program block that is
the calling source.
Since the output variables of the function block have been passed to the write-protected label/device, a conversion error has
occurred in the above example.
■Restrictions for module function blocks
The following describes the restrictions for the use of module function blocks.
• Do not turn off the contact of the MC instruction when calling a module function block between the MC instruction and MCR
instruction.
• Do not perform the jump processing that prevents module function blocks from being called by the CJ instruction.
• Execute a subroutine program every scan when calling a module function block in the subroutine program. Do not perform
the non-execution processing of a subroutine program by using the XCALL instruction.
• Do not call a module function block in an interrupt program or event execution type program.
• Do not call a module function block between the FOR and NEXT instructions, in the inline ST, or the control syntax of the
structured text language (IF statement, FOR statement, and CASE statement.)
■When a master control instruction is used
Shown here is the operation when the master control is OFF.
• Macro type function block
The operation in the function block is the same as contact OFF (OFF execution or no execution is made).
• Subroutine type function block and function
No execution is made in the function block.
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