Keithley 2651A Reference Manual page 145

Section 3: Functions and features
The source-measure unit (SMU) can be configured to perform any or all available measurements
during a sweep using the smua.trigger.measure.Y() function. To enable the measure action for
a simple synchronous sweep, set the smua.trigger.measure.action attribute to
smua.ENABLE. To enable the measure action for an asynchronous sweep, set the
smua.trigger.measure.action attribute to smua.ASYNC.
In asynchronous mode, trigger your measurements before the source completes the sweep (before
the end sweep action occurs).
Configured source and measure delays are imposed when the SMU executes the source and
measure action blocks. Additionally, if the measure count setting is greater than one, then the
measure count is satisfied each time the measure action is performed. Refer to
page 3-19) for information about configuring source and measure sweeps.
The arm and trigger counts must be set to control how many times the SMU executes the source and
measure actions. The arm count indicates the number of times to execute the complete sweep. The
trigger count sets the number of loops in the trigger layer. Typically, you set the trigger count to be
equal to the number of points in the configured sweep. If the trigger count is not equal to the number
of points configured in the sweep, then one of the following occurs:
•
If the trigger count is greater than the number of points in a sweep as configured by
smua.trigger.source.linearY(), smua.trigger.source.logY(), or
smua.trigger.source.listY(), then the SMU will satisfy the trigger count by restarting the
sweep values from the beginning.
•
If the trigger count is less than the number of source values configured, then the SMU will satisfy
the trigger count and ignore the remaining source values.
For example, configure a three-point linear voltage sweep from 1 to 3 V, with the trigger count set to
2. The SMU will output 1 V, 2 V. If the trigger count is set to 6, then the SMU will output the values
1 V, 2 V, 3 V, 1 V, 2 V, 3 V, repeating the source values twice in a single sweep.
Enabling pulse mode sweeps using the end pulse action
Enable pulse mode sweeps using the end pulse action. The example command below illustrates how
to configure pulse mode sweeps by setting the end pulse action:
smua.trigger.endpulse.action = smua.SOURCE_IDLE
Timers can be used to configure the pulse width and period (see
information). To disable pulse mode sweeps, set the smua.trigger.endpulse.action attribute
to smua.SOURCE_HOLD.
3-38
Model 2651A High Power System SourceMeter® Instrument Reference Manual
NOTE
Sweep Operation
Timers (on page 3-43) for more
2651A-901-01 Rev. A / March 2011
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