Tektronix Keithley 2651A Reference Manual page 603

Section 7: TSP command reference
smuX.measure.rangeY
This attribute contains the positive full-scale value of the measurement range for voltage or current.
Type TSP-Link accessible
Attribute (RW) Yes
Usage
rangeValue = smuX.measure.rangeY
smuX.measure.rangeY = rangeValue
rangeValue
X
Y
Details
Reading this attribute returns the positive full-scale value of the measurement range that the SMU is
currently using. Assigning a value to this attribute sets the SMU on a fixed range large enough to
measure the assigned value. The instrument selects the best range for measuring a value of
rangeValue.
This attribute is primarily intended to eliminate the time that is required by the automatic range
selection performed by a measuring instrument. Because selecting a fixed range prevents
autoranging, an overrange condition can occur. For example, measuring 3.0 V on the Model 2651A 1
V range causes an overrange. The value 9.91000E+37 is returned when this occurs.
If the source function is the same as the measurement function (for example, sourcing voltage and
measuring voltage), the measurement range is locked to be the same as the source range. However,
the setting for the measure range is retained. If the source function is changed (for example, from
sourcing voltage to sourcing current), the retained measurement range is used.
Model 2651A example: Assume the source function is voltage. The source range is 1 V and you set
the measure range for 10 V. Since the source range is 1 V, the SMU performs voltage measurements
on the 1 V range. If you now change the source function to current, voltage measurements are
performed on the 10 V range.
Explicitly setting a measure range disables measure autoranging for that function. Autoranging is
controlled separately for each source and measurement function: source voltage, source current,
measure voltage and measure current. Autoranging is enabled for all four by default.
Changing the range while the output is off does not update the hardware settings, but querying
returns the range setting that is used when the output is turned on. Setting a range while the output is
on takes effect immediately.
With measure autoranging enabled, the range is changed only when a measurement is made.
Querying the range after a measurement returns the range selected for that measurement.
7-258
Model 2651A High Power System SourceMeter® Instrument Reference Manual
Affected by
Instrument reset
SMU reset
Recall setup
Set to the maximum expected voltage or current to be measured
Source-measure unit (SMU) channel (for example, smua.measure.rangev
applies to SMU channel A)
SMU measurement function (v = voltage, i = current)
Where saved Default value
Saved setup Current:
100e-9 (100 nA)
Voltage: 100e-3 (100 mV)
2651A-901-01 Rev. C October 2021