DMM Measurement Defaults

The following table lists the default measurement settings for the NI 4070/4071/4072.

Function	Aperture	Auto Zero	ADC Calibration	DC Noise Rejection
DC 7½ digits1	100 ms	ON	ON	High-Order
DC 6½ digits	100 ms	ON	ON	High-Order
DC 5½ digits	500 µs (NI 4070/4072) 500 µs2 (NI 4071)	ONCE	OFF	Second-Order
DC 4½ digits	20 µs (NI 4070/4072) 50 µs (NI 4071)	ONCE	OFF	Second-Order
DC Auto Range	500 µs	ONCE	OFF	Second-Order
AC	Max (DC or 4/(minFreq))	OFF	OFF	N/A
AC Auto Range	Max (500 µs or 4/(minFreq))	OFF	OFF	N/A
Frequency	2/(minFreq)	N/A	N/A	N/A
Period	2 x (the maximum period)	N/A	N/A	N/A
Capacitance and Inductance	Inductance (only) at 10 kHz = 13.65 ms Inductance and capacitance at 1 kHz = 125.2 ms Inductance and capacitance at 91 Hz = 1.081 s	N/A	N/A	N/A
1The default Number of Averages for the NI 4071 is 4. 2For the NI 4071, on the 5.5 DCV 100V range, use 1.6 ms.

By default, the Aperture time, Auto Zero, ADC Calibration, DC Noise Rejection settings for a measurement are chosen by the driver based on the configured measurement and resolution. These values are chosen to ensure accuracy for 6½–digit or 7½–digit measurements while not sacrificing performance at lower resolutions. For more information on a particular attribute, including how to configure a non-default setting, refer to Features. For AC, excluding Auto Range, the aperture is expressed as Max (DC or 4/minFreq). minFreq, or minimum frequency, is a user–programmable parameter with a default value of 20 Hz. Therefore, the aperture default is 200 ms.

The same applies for other user selectable values of minFreq. For example, on the NI 4070/4071/4072, if a minFreq of 1 kHz is selected then 4/minFreq = 4/1 kHz = 4 ms. In this case 4 ms would be used as the AC aperture for resolutions <6 digits. For resolutions >6 digits, 100 ms would be used.

To adjust the default aperture time, refer to Configuring Measurement Timing.

Default Settling Times

Function	Settling Time
DC V (100 mV–10 V)	1 ms
DC V (100 V, 300 V) (NI 4070/4072 only)	2 ms
DC V (100 V, 1000 V) (NI 4071 only)	5 ms
DCV Auto Range	2 ms
Resistance ≤1 kΩ	1 ms
Resistance 10 kΩ	5 ms
Resistance 100 kΩ	25 ms
Resistance 1 MΩ	100 ms
Resistance ≥ 10 MΩ	250 ms
Resistance Auto Range	50 ms
AC V DC coupled	3 µs
AC V AC coupled	1 s
Frequency/Period	500 ms
DC I	100 µs
AC I	3 µs
Diode	10 ms
Inductance (NI 4072 only)	3 µs
Capacitance (NI 4072 only)	3 µs

To adjust the default settling times, refer to Configuring Measurement Timing.