Keithley 2651A Reference Manual page 635

Model 2651A High Power System SourceMeter® Instrument Reference Manual
Usage
SweepILogMeasureV(smu, starti, stopi, stime, points)
smu
starti
stopi
stime
points
Details
Data for voltage measurements, current 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 current sweep with voltage measured at every step (point):
1. Sets the smu to output starti amperes value, allows the source to settle for stime seconds,
and then performs a voltage measurement.
2. Sets the smu to output the next amperes step, allows the source to settle for stime seconds, and
then performs a voltage measurement.
3. Repeats the above sequence until the voltage is measured on the stopi amperes 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) * starti
2651A-901-01 Rev. A / March 2011
®
System SourceMeter instrument channel (set to smua)
Sweep start current in amperes
Sweep stop current in amperes
Settling time in seconds; occurs after stepping the source and before performing a
measurement
Number of sweep points (must be ≥2)
Figure 107: SweepILogMeasureV()
stime
starti
stime
Section 7: Command reference
stopi
stime
= Voltage measurement
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