Keithley 2601 Reference Manual page 323

Series 2600 System SourceMeter® Instruments Reference Manual
smuX.measure.rangeY
Attribute Fixed measure range for voltage or current.
Usage rangeval = smuX.measure.rangeY -- Reads measure range.
smuX.measure.rangeY = rangeval -- Writes measure range.
rangeval
Remarks • Reading this attribute returns the positive full-scale value of the measure range the SMU
is currently using.
• Assigning to this attribute sets the SMU on a fixed range large enough to measure the
given value. The instrument will select the best range for measuring a value of
rangeval.
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 auto-ranging, an over-range condition can occur, for example,
measuring 10.0V on the Model 2601/2602 6V range or measuring 5.0V on the
Model 2611/2612 2V range will cause an over-range. 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 voltage measure range is retained and used
when the source function is changed to current, and the present voltage measurement
range will be used.
• Model 2601/2602 example: Assume the source function is voltage. The source range is
1V and you set the measure range for 6V. Since the source range is 1V, the SMU will
perform voltage measurements on the 1V range. If you now change the function to
current, measurements will be performed on the 6V range.
• Explicitly setting either a source or measurement range for a function will disable auto
ranging for that function. Auto ranging is controlled separately for each source and
measurement function: source voltage, source current, measure voltage and measure
current. Auto ranging 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 source auto ranging enabled, the output level controls the range. Querying the
range after the level is set will return the range the unit chose as appropriate for that
source level.
• With measure auto ranging 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.
Details See "Range" in
Also see smuX.measure.autorangeY
Example Selects 1V measure range for Model 2601/2602 SMU A:
smua.measure.rangev = 0.5
2600S-901-01 Rev. C / January 2008
X = SMU channel (a or b)
Y = SMU measure function (v or i)
where v = voltage, i = current
Set to the expected voltage or current to be
measured.
Section 6.
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Section 12: Instrument Control Library
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