Programming instructions

© National Instruments Corporation 12-1 LabVIEW Data Acquisition Basics Manual
12
Buffering Your Way through
Waveform Generation
In Chapter 10,
Things You Should Know about Analog Output
, you learned
when to use buffered analog updates. This chapter shows you which VIs to
use in LabVIEW to perform these updates.
Buffered Analog Output
You can program single-buffered analog output in LabVIEW using an Easy
Analog Output VI, AO Generate Waveforms VI, as shown in Figure 12-1.
This VI writes an array of output values to the analog output channels at
a rate specified by
update rate
. For example, if
channels
consists of
two channels and the
waveforms
two-dimensional array consists of
two columns containing data for the two channels, LabVIEW writes values
from each column to the corresponding channels at every update interval.
After LabVIEW writes all the values in the two-dimensional array to the
channels, the VI stops. The signal level on the output channels maintains
the value of the final value row in the two-dimensional array until
another value is generated. If you use channel names configured in the
DAQ Channel Wizard in
channels
,
waveforms
is relative to the units
specified in the DAQ Channel Wizard. Otherwise,
waveforms
is relative
to volts.
Easy VIs contain error handling. If an error occurs in the AO Generate
Waveforms VI, a dialog box appears displaying the error number and
description, and the VI stops running.