Configuring Auto Range

Auto Range allows you to measure a signal when you do not know which range to select. The DMM takes a series of measurements and adjusts the range until the measurement falls within the smallest range appropriate for that measurement.

Auto Range uses the configuration you specify. Refer to the Measurement Defaults section for your device for more information on the configuration of Auto Range measurements.

Note   
  • The NI 4080/4081/4082 does not support Auto Range for Frequency Voltage.
  • For the NI 4065 and NI 4070/4071/4072, Auto Range uses the same configuration as 5½–digit measurements.
  • The NI 4081 does not support Auto Range when the input impedance is greater than 10 GΩ.
  • Auto Range does not adjust for the extended 200 MΩ range in 2-wire resistance measurements.
  • On the NI 4080/4081/4082 and NI 4070/4071/4072, Auto Range is unavailable during diode measurements and waveform acquisitions.
  • Auto Range reduces the reading rate of your measurements because the DMM takes an Auto Range reading before each measurement.
  • The NI 4065 only supports Auto Range when the trigger and sample trigger are set to IMMEDIATE.
  • DC current Auto Range on the NI 4081 and NI 4071 does not support the 1 µA and 10 µA ranges. For low currents, the NI 4081 and NI 4071 only Auto Ranges down to 100 µA. This behavior prevents an electromechanical relay from switching between these ranges (especially when high-compliance voltages could be present) thereby lengthening the life of the relay.
  • Auto Range is not supported for inductance or capacitance measurements. Inductance and capacitance measurements are only supported on the NI 4082 and NI 4072.

To enable Auto Range, complete the following steps:

  • LabVIEW
    1. Insert niDMM Config Measurement into the block diagram.
    2. Set Range to the desired Auto Range value (refer to the following table).
  • CVI/C++/Visual Basic
    1. Use niDMM_ConfigureMeasurementDigits.
    2. Set Range to the desired Auto Range value (refer to the following table).
Values Description
ON (–1) An Auto Range measurement is performed prior to each measurement.
OFF (–2) Use after a measurement that used Auto Range ON to set the DMM to the currently selected range.
ONCE (–3) NI-DMM picks a range for the first point and uses that range for the remaining measurements.
Tip Use niDMM Get Auto Range Value or niDMM_GetAutoRangeValue to retrieve the actual range used for a measurement.