Keithley 2651A Reference Manual page 511

Model 2651A High Power System SourceMeter® Instrument Reference Manual
Usage
rangeValue = smuX.measure.rangeY
smuX.measure.rangeY = rangeValue
rangeValue
X
Y
Details
Reading this attribute returns the positive full-scale value of the measure range 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 will select the best range for measuring a value of rangeValue.
This attribute is primarily intended to eliminate the time required by the automatic range selection performed by a
measuring instrument. Because selecting a fixed range will prevent autoranging, an over-range condition can
occur. For example, measuring 3.0 V on the Model 2651A 1 V range will cause 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 will be 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 will perform voltage measurements on the 1 V range. If
you now change the source function to current, voltage measurements will be performed on the 10 V range.
Explicitly setting a measure range will disable 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 will not update the hardware settings, but querying will return the
range setting that will be used once the output is turned on. Setting a range while the output is on will take effect
immediately.
With measure autoranging enabled, the range will be changed only when a measurement is taken. Querying the
range after a measurement will return the range selected for that measurement.
Example
smua.measure.rangev = 0.5
Also see
reset() (on page 7-151)
smuX.measure.autorangeY
smuX.source.rangeY
smuX.reset()
setup.recall()
Range (on page 2-65)
2651A-901-01 Rev. A / March 2011
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).
(on page 7-191)
(on page 7-223)
(on page 7-209)
(on page 7-170)
Selects the 1 V measurement range for SMU Channel A.
Section 7: Command reference
7-203