Programming instructions

Chapter 17 Shaking Hands with a Digital Partner
© National Instruments Corporation 17-7 LabVIEW Data Acquisition Basics Manual
Simple Buffered Examples
The block diagram in Figure 17-5 uses the Intermediate VIs to perform
pattern generation using the DIO-32 Series devices. An example VI
included with LabVIEW similar to the diagram below is the Digital
Buffered Handshaking VI, found in
labview\examples\daq\
digital\digio.llb
. Notice the
port list
contains more than one port
number, which means the ports are grouped together.
Figure 17-5.
Pattern Generation Using the DIO-32 Series Devices
The For Loop generates the digital data to output. The amount of data
generated equals the number of ports in the
port list
multiplied by the
number of updates
. The
direction
input specifies whether the ports
are configured for input or output. The DIO Wait VI waits until the digital
buffered input or output operation completes before returning to the
main VI. The DIO Clear VI halts any transfers and clears the group port
configuration. If you want an external source to supply the handshaking
signals, you can specify the
handshake source
to be an external signal
entering through the I/O connector (
handshake source
= 2 which is the
default value) or the RTSI connector (
handshake source
= 3). You only
need to use the
clock frequency
if you are performing pattern generation
(having an internal handshake source).