2Features and Functions
Measurement Resolution
Resolution is expressed in number of digits the internal DMM can measure or display on the front panel. You can set the resolution to 4, 5, or 6 full digits, plus a “½” digit which can be “0” or “1”. To increase the measurement accuracy and improve noise rejection, select 6½ digits.
To increase the measurement speed, select 4½ digits.
•For ac voltage measurements, the resolution is fixed at 6½ digits. The only way to control the reading rate for ac measurements is by changing the channel delay (see page 53) or by setting the ac filter to the highest frequency limit (see page 36).
•The specified resolution is used for all measurements on the selected channel. If you have applied Mx+B scaling or have assigned alarms to the selected channel, those measurements are also made using the specified resolution. Measurements taken during the Monitor function also use the specified resolution.
•Changing the number of digits does more than just change the resolution of the instrument. It also changes the integration time, which is the period the instrument’s analog- to- digital (A/D) converter samples the input signal for a measurement. See “Custom A/D Integration Time” on page 19 for more information.
•The CONFigure and MEASure? commands contain an optional parameter which allows you to specify the resolution.
•The instrument returns to 5½ digits when the measurement function is changed and after a Factory Reset (*RST command). An Instrument Preset (SYSTem:PRESet command) or Card Reset (SYSTem:CPON command) does not change the resolution setting.
Front Panel Operation: DMM or Channel (Configure) > INTEGRATION > NPLC
First, select the measurement function on the active channel. You are automatically guided to the next level of the menu where you can select a specific resolution.
Remote Interface Operation: Specify the resolution in the same units as the measurement function, not in number of digits. For example, if the function is dc voltage, specify the resolution in volts. For frequency, specify the resolution in hertz.
You can select the resolution using parameters in the CONFigure and MEASure? commands. For example, the following command selects the 10 Vdc range with 4½ digits of resolution on the specified channel.
CONF:VOLT:DC 10,0.001,(@3001)
18 | 34980A User’s Guide |
