When specifying a range for a voltage or current measurement, you can select
to measure a signal when you do not know which range to select. The digital multimeter (DMM) takes a series of measurements and adjusts the range until the measurement falls within the smallest range appropriate for that measurement.
Auto—Takes a reading before each measurement to select the smallest appropriate range.
Auto once—The first point measured determines the range for the reast of the measurements.
For model-specific considerations when using Auto Range, refer to
Configuring Auto Range
in NI-DMM documentation.