Keithley System SourceMeter 2601B, Reference Manual

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Section 2: General operation Series 2600B System SourceMeter® Instrument Reference Manual
2-32 2600BS-901-01 Rev. B / May 2013
Remote command autozero
To set autozero from a remote interface:
Use the autozero command with the appropriate option shown in the following table to set autozero
through a remote interface (see
smuX.measure.autozero (on page 7-199)). For example, send the
following command to activate channel A automatic reference measurements:
smua.measure.autozero = smua.AUTOZERO_AUTO
Autozero command and options
Command** Description
smu X .measure.autozero = smu X .AUTOZERO_OFF
Disable autozero*
smu X .measure.autozero = smu X .AUTOZERO_ONCE
After immediately taking one reference and one zero
measurement, turns automatic reference measurements
off.
smu X .measure.autozero = smu X .AUTOZERO_AUTO
Automatically takes new acquisitions when the Series
2600B determines reference and zero values are out-of-
date.
* Old NPLC cache values will be used when autozero is disabled (see NPLC caching (on page 2-32)).
**
smu X
: For Models 2601B, 2611B, and 2635B, this value is
smua
(SMU Channel A); for Models 2602B, 2604B, 2612B,
2614B, 2634B, and 2636B, this value can be
smua
(for SMU Channel A) or
smub
(for SMU Channel B).
NPLC caching
NPLC caching speeds up operation by caching A/D reference and zero values for up to the ten most
recent measurement aperture settings. Whenever the integration rate is changed using the SPEED
key, or a user setup is recalled, the NPLC cache is checked. If the integration rate is already stored in
the cache, the stored reference and zero values are recalled and used. If the integration rate is not
already stored in the cache, a reference and zero value will be acquired and stored in the cache when
the next measurement is made. If there are already ten NPLC values stored, the oldest one will be
overwritten by the newest one. When autozero is off, NPLC values stored in the cache will be used
regardless of age.
Basic source-measure procedure
Front-panel source-measure procedure
Use the following procedure to perform the basic source-measure operations of the Series 2600B.
The following procedure assumes that the Series 2600B is already connected to the device under test
(DUT), as explained in
DUT test connections (on page 2-48).
Hazardous voltages may be present on all output and guard terminals. To prevent electrical
shock that could cause injury or death, never make or break connections to the Series
2600B while the instrument is powered on. Turn off the equipment from the front panel or
disconnect the main power cord from the rear of the Series 2600B before handling cables.
Putting the equipment into standby does not guarantee that the outputs are powered off if a
hardware or software fault occurs.