Keithley 2651A Reference Manual page 639

Model 2651A High Power System SourceMeter® Instrument Reference Manual
Usage
SweepVLogMeasureI(smu, startv, stopv, stime, points)
smu
startv
stopv
stime
points
Details
Data for current measurements, voltage source values, and timestamps are stored in smuX.nvbuffer1.
If all parameters are omitted when this function is called, this function is executed with the parameters set to the
default values.
Performs a logarithmic voltage sweep with current measured at every step (point):
1. Sets the smu to output startv amperes, allows the source to settle for stime seconds, and then
performs a current measurement.
2. Sets the smu to output the next volts step, allows the source to settle for stime seconds, and
then performs a current measurement.
3. Repeats the above sequence until the voltage is measured on the stopv volts step.
The source level at each step (SourceStepLevel) is automatically calculated as follows:
MeasurePoint = The step point number for a measurement
For example, for a five-point sweep (points = 5), a measurement is performed at MeasurePoint 1, 2, 3, 4,
and 5.
LogStepSize = (log10(stopi) – log10(starti)) / (points – 1)
LogStep = (MeasurePoint – 1) * (LogStepSize)
SourceStepLevel = antilog(LogStep) * startv
2651A-901-01 Rev. A / March 2011
®
System SourceMeter instrument channel (set to smua)
Sweep start voltage in volts
Sweep stop voltage in volts
Settling time in seconds; occurs after stepping the source and before performing a
measurement
Number of sweep points (must be ≥2)
Figure 109: SweepVLogMeasureI()
stime
startv
stime
Section 7: Command reference
stopv
stime
= Current measurement
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