NI-DAQmx Hardware Timed Single Point AI with LabWindows CVI

This example program demonstrates how to use the Hardware Timed Single Point sampling mode in the LabWindows CVI environment.

ContAcq-IntClk (HW Timed).c demonstrates the hardware timed, non-buffered technique of data acquisition. The scan clock on the board controls acquisition timing. Acquired scans are read directly from the device's FIFO using DAQmxReadAnalogF64.

The acquisition is configured with no buffer, and the on-board sample clock started at the selected acquisition rate. The SampleCompleteEvent is utilized in this program.  When a sample is ready to be read, the SampleCompleteEvent fires the SignalCallback function.  Each time the callback is fired, a single sample is read from the FIFO.  If a sample is missed because the acquisition does not keep up, an error message will be displayed, and the acquisition stopped. 

A common reason to use non-buffered acquisition is that some kind of processing needs to be done for each data point. The acquisition rate you can achieve depends on many system-dependent variables.  Some of these include the operating system, processing power of the computer, other CPU-intensive tasks that are running at the same time, etc.  .

Before running this program, please read the comments at the top of the program.  These comments are documented below.

Instructions for Running:
1. Select the physical channel to correspond to where your signal is input on the DAQ device.
2. Enter the minimum and maximum voltage range.
Note: For better accuracy try to match the input range to the expected voltage level of the measured signal.
3. Set the rate of the acquisition. Also set the Samples per Channel control. This will determine how many samples are
read at a time.
Note: The rate should be at least twice as fast as the maximum frequency component of the signal being acquired.

Requirements

Filename: cont_acq-intclk_hw_timed.c

Software Requirements

Application Software: LabWindows/CVI Full Development System 8.5
Language(s): C

Hardware Requirements

Hardware Group: Multifunction DAQ (MIO)
Driver: NI-DAQmx 8.7

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