Instructions

Section
5: Measuring DC voltage with high accuracy Model DMM6500 6½ Digit Multimeter
User's Manual
5-6 DMM6500-900-01 Rev. B / August 2019
Send the following commands for this example application:
-- Reset the instrument to the default settings.
reset()
-- Set the measure function to DC voltage.
dmm.measure.func = dmm.FUNC_DC_VOLTAGE
-- Set the measurement range to 10 V.
dmm.measure.range = 10
-- Set the number of power line cycles to 10.
dmm.measure.nplc = 10
-- Set the input impedance to auto so it selects 10 Gohm for the 10 V range.
dmm.measure.inputimpedance = dmm.IMPEDANCE_AUTO
-- Enable autozero.
dmm.measure.autozero.enable = dmm.ON
-- Set the averaging filter type to repeating.
dmm.measure.filter.type = dmm.FILTER_REPEAT_AVG
-- Set filter count to 100.
dmm.measure.filter.count = 100
-- Enable the filter.
dmm.measure.filter.enable = dmm.ON
-- Read the voltage value.
print(dmm.measure.read())
Test results
The following table shows the trade-off between accuracy and measurement speed based on the
integration rate (NPLC), averaging filter, and autozero settings. The first row of data is measured
using the setup documented in this example. The other rows show the results as the integration rate,
filter, and autozero settings are changed.
DC voltage
Measurement time
(seconds)
Integration rate (NPLC) Filter Auto Zero
4.999985
33.542816
10
On
On
4.999982
0.335426
10
Off
On
4.999979
0.035426
1
Off
On
4.999990
0.017023
1
Off
Off
Figure 34: DC voltage high-accuracy test results