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Chapter 4 Using NI-IMAQdx in LabVIEW
© National Instruments Corporation 4-2 NI-IMAQdx User Manual
The Vision and Motion»NI-IMAQdx»NI-IMAQdx Low Level palette
contains VIs for more advanced applications.
Refer to the NI-IMAQdx VI Reference Help for more information about
using these VIs.
Common VI Parameters
The following sections describe commonly used VIs and important
parameters common to many VIs.
IMAQdx Session
IMAQdx Session is a unique identifier that specifies which interface file to
use for the acquisition. The IMAQdx Session is produced by the IMAQdx
Open Camera VI and used as an input to all other NI-IMAQdx VIs. The
NI-IMAQdx VIs use IMAQdx Session Out, which is identical to IMAQdx
Session, to simplify dataflow programming. IMAQdx Session Out is
similar to the duplicate file sessions provided by the file I/O VIs. The
high-level acquisition VIs—IMAQdx Snap, IMAQdx Configure Grab, and
IMAQdx Sequence—require you to wire IMAQdx Session In only in the
following instances:
• If you are using an interface other than the default
cam0
• If you are using multiple cameras
• If you need to set IMAQdx properties before the acquisition
To get and set properties of the acquisition and camera, wire the IMAQdx
Session to the LabVIEW property node.
Image Buffer
Many acquisition VIs require an image buffer to receive the captured
image. You can create this image buffer with IMAQ Create. Refer to the
Buffer Management section of this chapter for more information about
using buffers. Image In receives the image buffer. Image Out returns the
captured image.