User's Manual

NI cDAQ-9172 User Guide and Specifications 34 ni.com
The NI-DAQmx Help is available after installation from Start»
All Programs»National Instruments»NI-DAQ»NI-DAQmx Help.
To view the LabVIEW Help, in version 8.0 or later, select Help»Search the
LabVIEW Help in LabVIEW. Alternately, to download the LabVIEW
Help, go to
ni.com/manuals.
Using an Analog Source
Some C Series I/O modules can generate a trigger based on an analog
signal. In NI-DAQmx, this is called the Analog Comparison Event,
depending on the trigger properties.
When you use an analog trigger source, the samples are paused when the
Analog Comparison Event signal is at a high or low level, depending on
the trigger properties. The analog trigger circuit must be configured by
a simultaneously running analog input task.
Minimizing Glitches on the Output Signal
When you use a DAC to generate a waveform, you may observe glitches
on the output signal. These glitches are normal; when a DAC switches from
one voltage to another, it produces glitches due to released charges. The
largest glitches occur when the most significant bit of the DAC code
changes. You can build a lowpass deglitching filter to remove some of
these glitches, depending on the frequency and nature of the output signal.
Go to
ni.com/support for more information about minimizing glitches.
Getting Started with AO Applications in Software
You can use the NI cDAQ-9172 chassis in the following analog output
applications:
• Single-Point (On-Demand) Generation
• Finite Generation
• Continuous Generation
• Waveform Generation
For more information about programming analog output applications and
triggers in software, refer the LabVIEW Help, in version 8.0 or later, or to
the NI-DAQmx Help.
The NI-DAQmx Help is available after installation from Start»
All Programs»National Instruments»NI-DAQ»NI-DAQmx Help.
To view the LabVIEW Help, in version 8.0 or later, select Help»
Search the LabVIEW Help in LabVIEW. Alternately, to download
the LabVIEW Help, go to
ni.com/manuals.