Smux.measure.calibratey() - Keithley 2601B Reference Manual

Section 7: TSP command reference
Details
The analog-to-digital converter (ADC) uses a ratiometric A/D conversion technique. To ensure the accuracy of
readings, the instrument must periodically obtain new measurements of its internal ground and voltage
reference. The time interval between updates to these reference measurements is determined by the integration
aperture being used for measurements. The Series 2600B uses separate reference and zero measurements for
each aperture.
By default, the instrument automatically checks these reference measurements whenever a signal measurement
is made. If the reference measurements have expired when a signal measurement is made, the instrument will
automatically take two more A/D conversions, one for the reference and one for the zero, before returning the
result. Thus, occasionally, a measurement takes longer than normal.
This additional time can cause problems in sweeps and other test sequences in which measurement timing is
critical. To avoid the time that is needed for the reference measurements in these situations, you can use the
smuX.measure.autozero attribute to disable the automatic reference measurements.
Remember that disabling automatic reference measurements may allow the instrument to gradually drift out of
specification. To minimize the drift, a reference and zero measurement should be made just before any critical
test sequences. You can use the smuX.AUTOZERO_ONCE setting to force a refresh of the reference and zero
measurements that are used for the present aperture setting.
The Series 2600B stores the reference measurements for the last ten NPLC settings that were used in a
reference cache. If an NPLC setting is selected and an entry for it is not in the cache, the oldest (least recently
used) entry is discarded to make room for the new entry.
Example
smua.measure.autozero = 1
Also see
Autozero (on page 2-31)
reset() (on page 7-160)
smuX.measure.nplc
setup.recall()
smuX.reset() (on page 7-216)

smuX.measure.calibrateY()

This function generates and activates new measurement calibration constants.
Type TSP-Link accessible
Function Yes
Usage
smuX.measure.calibrateY(range, cp1Measured, cp1Reference, cp2Measured,
cp2Reference)
X
Y
range
cp1Measured
cp1Reference
cp2Measured
cp2Reference
7-200
(on page 7-208)
(on page 7-180)
Affected by
Source-measure unit (SMU) channel (for example,
smua.measure.calibratev() applies to SMU channel A)
SMU measurement function (v = voltage, i = current)
The measurement range to calibrate
The value measured by this SMU for calibration point 1
The reference measurement for calibration point 1 as measured externally
The value measured by this SMU for calibration point 2
The reference measurement for calibration point 2 as measured externally
Series 2600B System SourceMeter® Instrument Reference Manual
Performs autozero once for SMU channel A. Alternatively,
the value 1 may be replaced with smua.AUTOZERO_ONCE.
Where saved Default value
2600BS-901-01 Rev. B / May 2013