Resistance (4-Wire)

Configure four-wire resistance measurements.

Range

Use Auto to automatically select the range, or select a fixed manual range. Click the Auto-Select button to auto range for one measurement and then return to the fixed manual range mode. Manual ranging results in better measurement speed, since the DMM does not have to determine which range to use for each measurement. If the input signal is greater than can be measured on the selected range:

• In line chart view, the overload indication (+OVLD or -OVLD) is displayed above the chart and the overload reading is plotted off the top (+OVLD) or off the bottom (-OVLD) of the chart.
• In histogram view, the overload indication (+OVLD or -OVLD) is displayed above the histogram and the reading is placed in an outer bin to the right (+OVLD) or to the left (-OVLD) of the histogram. Outer bins are shown in red.

Aperture

Set the aperture time for the measurement in number of power-line cycles (NPLC) or in seconds (Aperture)/ resolution (Resolution). To obtain normal mode (line-frequency noise) rejection, select an integral number of power-line cycles (1, 2, 10, or 100 NPLC). For more information, see Aperture Time and Resolution.

Null State

Enable or disable the null measurement feature. This feature measures the difference between a stored null value and the input signal; Result = reading – null value. Select Value check box to enable this feature and enter a null value. Some DMMs have an Auto-Select selection. When Auto-Select is selected, the first reading taken is used as the null value for all subsequent measurements for this measurement function.

Offset Compensation

Enable (On) or disable (Off) offset compensation. When enabled, resistance readings are corrected for any voltage offset in the DMM's input circuitry. When enabled, offset compensation increases measurement time.