Hello,
'port' is an integer parameter referring to the general-purpose I/O port (1, 2, 3, or 4) or RTSI software port (9) to be read.
'portData' also is an integer parameter that returns the bitmap of the logical state of the I/O 'port' (i.e. 0 would mean that all lines are FALSE and 255 would mean that all 8 lines are TRUE)
See the following
example for a demonstration of this in Visual Basic.
Hope this helps!
Regards,
Yusuf C.
Applications Engineering
National Instruments