02-11-2016 01:49 AM - edited 02-11-2016 02:00 AM
What do you mean by "read one specific port"? The example you are looking at is targeted at counter measurement, based on your hardware it actually uses the only counter input that is present. To read a digital port you will need to use different resources: look at the examples in Hardware Input and Output >> DAQmx >> Digital Measurements branche of the example finder tree.
By the way, the counter input is different from digital channels inputs: to count events you need to connect your signal to PFI0 terminal, while to read digital signals you must use one of PX.y terminals: refer to your board specifications for additiona details. By the way, remember that 6009 only counts on the falling edge, and this explains the -200077 error you were getting.
02-11-2016 02:06 AM
If you are new to DAQmx, you should consider reading some documentation: NI-DAQmx Key Concepts chapter in DAQmx help can give you the fundamentals on data acquisiition, while reading the board specifications and user guide can clarify which resources offers the board and how to use and connect to it