DMM6500 6½ Digit Multimeter User's Manual
Section 5: Measuring DC voltage with high accuracy
DMM6500-900-01Rev. A / April 2018
5-3
There is no internal connection between protective earth (safety ground) and the LO
terminals of the DMM6500. Therefore, hazardous voltages (more than 30 V
RMS
) can appear on
LO terminals. This can occur when the instrument is operating in any mode. To prevent
hazardous voltage from appearing on the LO terminals, connect the LO terminal to protective
earth (safety ground) if your application allows it. You can connect the LO terminal to the
chassis ground terminal on the front panel or the chassis ground screw terminal on the rear
panel. Note that the front-panel terminals are isolated from the rear-panel terminals.
Therefore, if you are using the front-panel terminals, ground to the front-panel LO terminal. If
using the rear-panel terminals, ground to the rear panel LO terminal. Failure to follow these
guidelines can result in injury, death, or instrument damage.
Measuring DCV with high accuracy
This application demonstrates how to use the DMM6500 to make high-accuracy DC voltage
measurements. You can make the measurements from the front-panel interface or over the remote
interface using SCPI code or TSP code. For information about setting up remote communications,
see
Remote communications interfaces
(on page 3-1).
For this application, you will:
•
Restart the instrument.
•
Set the range to 10 V.
•
Select the DC voltage function.
•
Set the integration rate to 10 power line cycles (PLCs) at 60 Hz line frequency; 10 PLCs provide
an aperture of 166.7 ms.
•
Set the input impedance to Auto.
•
Turn on autozero. This allows the instrument to optimize the accuracy of readings by checking
reference measurements.
•
Enable a repeating filter with a count of 100. This reduces noise error because the results are
more stable when the measurements are averaged.
•
Generate readings from the front panel or the remote interface.
