Hardware-Timed, Non-Buffered Analog Acquisition

Cont(inuous) Acq(uire) & Chart (hw timed) 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 AI Single Scan.

The acquisition is configured with no buffer, and the on-board scan clock started at the selected scan rate. In the first loop iteration, the newest (most recent) scan is read from the FIFO. In each subsequent loop iteration AI Single Scan is called to read the oldest scan from the FIFO. Then if a scan is missed because the acquisition does not keep up, an error message will be displayed, and the acquisition stopped. Each scan is plotted on the chart after it is read.
A common reason to use non-buffered acquisition is that some kind of processing needs to be done for each data point. You will probably want to add more functions to the diagram to customize this VI for your application. The acquisition rate you can achieve depends on how much processing and display the VI must do. This VI calls a subVI named My Single-Scan Processing. Add whatever processing you need to this subVI, or replace it with one of your own. The data processing subVI also demonstrates how to use error clusters in your own subVIs, so they can be included in the error data flow chain.

Before running this VI, set the values of the controls on the front panel. Select Show Help Window from the Help menu to see a description of each control. If the values you select for all the controls are values you will usually use, select Make Current Values Default from the Operate menu and save the VI. Or, you may save individual control's default values by popping up on the control, selecting Data Operations, then selecting Make Current Value Default, and saving the VI.

Requirements

Filename: cont_acq&chart__hw_timed_.zip

Software Requirements

Application Software: LabVIEW Full Development System 5.0.1
Language(s): LabVIEW

Hardware Requirements

Hardware Group: Multifunction DAQ (MIO)
Driver: Traditional NI-DAQ (Legacy)

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