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Another application of continuous acquisition is fetching a few of the most recent data points. This technique is useful if you want chunks of nontriggered data with the same configuration parameters. It avoids the software overhead necessary to reconfigure the acquisition, and your program never needs to wait for the data to be acquired.
To fetch the most recent data, initiate an infinite acquisition—one that never triggers—by configuring software triggering. When you want the most recent data points, call a Fetch function with the Fetch Relative To attribute set to now, which specifies that the offset is from the last sample acquired by the digitizer. You must set the Fetch Offset attribute to the negated number of samples you want.