Create a known voltage output in Measurement & Automation Explorer through
Test Panels and read the corresponding input value as shown below.
Expand NI-DAQmx Devices from the configuration tree. Select your device and click Test Panels on the toolbar, as shown in figure below.
From the test panel of your device, click the Analog Output tab. In Channel Name select a device supported analog output channel, enter an Output Value, and click Update. The step is shown in figure below.
Without closing the test panel window, select Analog Input. In Channel Name select the same analog output channel and its corresponding ground. Click Start and the chart should begin updating with the value entered from the Analog Output tab. The step is shown in figure below.
Additional Information
If a more sophisticated loopback test is required you can also use these internal channels in LabVIEW, as shown in figure below.
In order to see this channel, you must change the I/O filtering of this control. For instructions on how to do this, see
How do I Access Internal Channels on my DAQ Device using DAQmx?