Programming instructions

Chapter 3 Basic LabVIEW Data Acquisition Concepts
© National Instruments Corporation 3-15 LabVIEW Data Acquisition Basics Manual
iteration of the outer loop. If you were to label your index selectors for a
row major 2D array, the array might look like Figure 3-11.
Figure 3-11.
2D Array in Row Major Order
You also can organize 2D array data by columns. The Analog Input VIs in
LabVIEW organize their data in this way. Each column holds data from one
channel, so selecting a column selects a channel. Selecting a row selects
a scan of data. This ordering method is often called
column major order
.
If you were to label your index selectors for a column major 2D array, the
array might look like Figure 3-12.
Figure 3-12.
2D Array in Column Major Order
To graph a column major order 2D array, you must configure the waveform
chart or graph to treat the data as transposed by turning on this option in the
graph pop-up menu.
Note
This option appears in gray until you wire the 2D array to a graph. To convert
the data to row major order, select Functions»Array & Cluster»Transpose
2D Array.
If you want to extract a single channel from a column major 2D array,
use the Index Array function from
Functions»Array & Cluster
. Add a
dimension so that you have two black rectangles in the lower left corner.
The top rectangle selects the row and the bottom rectangle selects the
column. Popup on the row rectangle and select
Disable Indexing
. Now,
when you select a column (or channel) by wiring your selection to the