With the 'io_function_block' attribute, you mark a function block in order to prepare it for the assignment to
a channel in the I/O mapping of the device configuration. Then it is shown in the “Select function block” dialog.
With the 'io_function_block_mapping' attribute, you mark a parameter that should be used when mapping the FB to a device
channel in this kind of function block. You can provide the attribute to multiple
parameters of the function block. For I/O mapping, the first one is used automatically whose type matches the channel (input,
output, data type).
Syntax:
{attribute 'io_function_block'}
{attribute 'io_function_block_mapping'}
Insert location: The line above the first line in the declaration of the function block, or the line above the parameter declaration.
Example
{attribute 'io_function_block'}
FUNCTION_BLOCK Scale_Output_Int
VAR_INPUT
iInput : INT;
iNumerator : INT;
iDenominator : INT :=1;
iOffset : INT := 0;
END_VAR
VAR_OUTPUT
{attribute 'io_function_block_mapping'}
iOutput : INT;
END_VAR
VAR