Agilent Technologies n3300a DC Measurements, RMS Measurements, Minimum and Maximum Measurements

General Information - 2

As shipped from the factory, front panel measurements for input voltage and current are calculated from a total of 1000 readings taken at a 10 microsecond sampling rate. There are no trigger controls for front panel measurements. However, you can program both the sampling rate and the number of data points in each front panel measurement using commands in the Sense menu. With this flexibility, measurement accuracy can be improved for waveforms with frequencies as low as several Hertz. The sample buffer size may be varied from 1 to 4096 data points. The sampling rate may be varied from 0.000001 seconds to 0.032 seconds. Values are rounded to the nearest 10-microsecond interval.

DC Measurements

DC voltage and current is measured by acquiring a number of readings at the selected time interval, applying a windowing function to the readings, and averaging the readings. Windowing is a signal conditioning process that reduces the error in dc measurements made in the presence of periodic signals such as line ripple. At power-on and after a *RST command, the interval and number of sample points used for the measurement acquisition is set. Ripple rejection is a function of the number of cycles of the ripple frequency contained in the acquisition window. More cycles in the acquisition window results in better ripple rejection. In addition, the speed of the measurement can be increased by reducing the number of sample points.

To measure the dc input voltage or current using the front panel, press the Meter key. The display indicates the present voltage and current reading. Scroll to the appropriate measurement. To measure the voltage or current over the GPIB, use the MEAS:VOLT? or MEAS:CURR? command.

RMS Measurements

To measure the rms of the input voltage or current, press the Meter key and scroll to the V RMS or A RMS menu commands. To measure the rms voltage or current over the GPIB, use MEAS:VOLT:ACDC? or

MEAS:CURR:ACDC?

This returns the total rms measurement, including the dc portion.

Minimum and Maximum Measurements

To measure the maximum or minimum voltage or current, press the Meter key and scroll to the

V MAX, V MIN, A MAX, or A MIN menu commands. Minimum returns the lowest value in the array; maximum returns the highest value in the array. To measure the maximum/minimum voltage or current over the GPIB, use MEAS:VOLT:MAX?/MEAS:VOLT:MIN? or MEAS:CURR:MAX?/MEAS:CURR:MIN?

Power Measurements

To measure the average, maximum, or minimum power, press the Meter key and scroll to the WATTS, W MAX, or W MIN menu commands. Power is calculated from the latest voltage and current measurements. Use MEASure:POWer? to measure power over the GPIB.

Measurement Ranges

The electronic load has two measurement ranges. The commands that control the measurement ranges are located in the front panel Sense menu. To change measurement ranges, scroll to the S:C:RNG or the S:V:RNG commands and enter a value that falls within the range that you wish to set. The electronic load will pick the range with the best resolution for that value. The corresponding SCPI range commands are: SENS:CURR:RANG and SENS:VOLT:RANG.

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