Programming instructions

Appendix A LabVIEW Data Acquisition Common Questions
LabVIEW Data Acquisition Basics Manual A-2
© National Instruments Corporation
How can I tell when a continuous data acquisition operation does not
have enough buffer capacity?
The scan backlog rises with time, either steadily or in jumps, or takes a long
time to drop to normal after an interrupting activity like mouse movement.
If you can open another VI during the operation without receiving an
overrun error you should have adequate buffer capacity.
I want to group two or more ports using my DIO32, DIO24, or
DIO-96 board, but I do not want to use handshaking. I just want to
read one group of ports just once. How can I set it up in software?
Use Easy I/O VIs (Write to Digital Port or Read from Digital Port) or
Advanced Digital VIs (DIO Port Config, DIO Port Write or DIO Port
Read), and set multiple ports in the port list. For Easy I/O VIs, you can
specify up to four ports in the port list. Whatever data you try to output to
each port of your “group” will correspond to each element of the data array.
This also applies for input.
I want to use the OUT1, OUT2, OUT3 and IN1, IN2, IN3 pins on my
DIO-32F board. How do I address those pins using the Easy I/O Digital
VIs in LabVIEW?
These output and inputs pins are addressed together as port 4. OUT1 and
IN1 are referred to as bit 0, OUT2 and IN2 are referred to as bit 1, and
OUT3 and IN3 are referred to as bit 2. Only the NB-DIO-32F has three pins
for each direction. If you use the Write To Digital Port VI, you will output
on the OUT pins, and if you use the Read From Digital Port VI, you will
input from the IN pins.
I want to be able to write up to four lines on the digital port on my
jumpered MIO (non E-series) board while also reading in four lines of
digital data on the remaining free digital lines. How do I do this?
Use the DIO Port Config VI twice; once to configure four lines for output
and once more to configure four lines for input. Now call the DIO Port
Write VI or the DIO Port Read VI for the appropriate lines. Avoid calling
the Easy I/O VIs for digital I/O, as they reconfigure the port direction each
time the VI is called.