Download Agilent Technologies 6633A User`s guide

Programming the DC Source - 7
Making Measurements
The Agilent 66111A and the Agilent 66311B both have excellent output voltage and current
measurement capability. The Agilent 66311B Mobile Communications Dc Source also has the ability to
make several types of voltage or current measurements. These expanded measurement capabilities are
particularly useful for loads that draw current in pulses.
NOTE:
Because there is only one measurement buffer, you cannot measure output voltage and
current simultaneously.
All measurements are performed by digitizing the instantaneous output voltage or current for a defined
number of samples and sample interval, storing the results in a buffer, and then calculating the measured
result. Many parameters of the measurement are programmable. These include the number of samples,
the time interval between samples, and the method of triggering. Note that there is a tradeoff between
these parameters and the speed, accuracy, and stability of the measurement in the presence of noise.
There are two ways to make measurements:
♦ Use the MEASure commands to immediately start acquiring new voltage or current data, and return
measurement calculations from this data as soon as the buffer is full. This is the easiest way to make
measurements, since it requires no explicit trigger programming.
♦ Use an acquisition trigger to acquire the data as discussed under “Triggering Measurements”. Then
use the FETCh commands to return calculations from the data that was retrieved by the acquisition
trigger. This method gives you the flexibility to synchronize the data acquisition with a transition in
the output voltage or current. FETCh commands do not trigger the acquisition of new measurement
data, but they can be used to return many different calculations from the data that was retrieved by
the acquisition trigger. Note that if you take a voltage measurement, you can fetch only voltage data.
NOTE:
For each MEASure query, there exists a corresponding FETCh query. FETCh queries
perform the same calculation as MEASure queries, but do not acquire new data.
Controlling Measurement Samples
You can vary both the number of data points in a measurement sample, as well as the time between
samples. This is illustrated in Figure 7-2.
SENS:SWE:TINT <time>
SENS:SWE:POIN <# of points>
Figure 7-2. Commands that Control Measurement Time
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