Agilent Technologies 6631B - Manual (Page 24)

3 - Programming the DC Source
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This results in a data acquisition time of 32 milliseconds. Adding a command processing overhead of
about 20 milliseconds results in a total measurement time of about 50 milliseconds per measurement
sample.
Ripple rejection is a function of the number of cycles of the ripple frequency contained in the acquisition
window. More cycles in the aquisition window results in better ripple rejection. If you increase the time
interval for each measurement to 45 microseconds for example, this results in 5.53 cycles in the
acquisition window at 60 Hz, for a ripple rejection of about 70 dB.
Note that the speed of the measurement can be increased by reducing the number of sample points. For
example, the commands
SENSe:SWEep:TINTerval 15E-6
SENSe:SWEep:POINts 1024
speeds up the acquisition period to 16 milliseconds; however, the tradeoff is reduced measurement
accuracy.
RMS Measurements (Agilent 66312A, 66332A Only)
To read the rms content of a voltage or current waveform, use:
MEASure:VOLTage:ACDC? or
MEASure:CURRent:ACDC?
This returns the total rms measurement, including the dc portion.
Making rms measurements on ac waveforms for which a non-integral number of cycles of data has been
acquired may result in measurement errors due to the last partial cycle of acquired data. The instrument
reduces this error by using a Hanning window function when making the measurement.
Minimum and Maximum Measurements (Agilent 66312A, 66332A Only)
To measure the maximum or minimum voltage or current of a pulse or ac waveform, use:
MEASure:VOLTage:MAXimum?
MEASure:VOLTage:MINimum?
MEASure:CURRent:MAXimum?
MEASure:CURRent:MINimum?
Current Ranges
The dc source has two current measurement ranges. The command that controls the ranges is:
SENSe:CURRent:RANGe MIN | MAX
When the range is set to MIN, the maximum current that can be measured is 20 milliamperes.
Returning Measurement Data From the Data Buffer (Agilent 66312A, 66332A Only)
The MEASure and FETCh queries can also return all data values of the instantaneous voltage or current
buffer. The commands are:
MEASure:ARRay:CURRent?
MEASure:ARRay:VOLTage?