Keithley SourceMeter 2400, User Manual

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11-6 Triggering 2400 Series SourceMeter
®
User’s Manual
MEASURE Action
— During this phase of the SDM cycle, the measurement process
takes place. If the repeat filter is enabled, as shown in the blow-up drawing for Measure
Action, the instrument samples the specified number of reading conversions to yield a sin-
gle filtered reading (measurement). If using the moving filter or if the filter is disabled,
only a single reading conversion will yield a reading.
Counters
Programmable counters are used to repeat operations within the trigger model layers. For
example, if performing a 10-point sweep, the trigger counter would be set to 10. Operation
will stay in the Trigger Layer until the 10 source-delay-measure points of the sweep are
performed.
If you wanted to repeat the sweep three times, the arm counter would be set to three. Three
10-point sweeps can then be performed for a total of 30 source-delay-measure actions.
Refer to the examples at the end of this section.
The maximum buffer size for the SourceMeter is 2500 readings. The product of the two
counter values cannot exceed 2500. For example, if you set an arm count of two, the max-
imum trigger count will be 1250 (2500 / 2 = 1250). However, you can set the arm count to
INFINITE. With an infinite arm count, the maximum trigger count is 2500.
NOTE When a sweep is configured, the trigger model settings will not change until the
sweep is started. After the sweep is finished, the trigger model will reset to the
previous settings.
Output triggers
The SourceMeter can be programmed to output a trigger (via rear panel Trigger Link
connector) after various trigger model operations. An output trigger is used to trigger
another instrument to perform an operation. See
“Trigger link,” page 11-19 , for more
information.
Trigger Layer Output Triggers — After each action (Source, Delay, and Measure), the
SourceMeter can be programmed to send out an output trigger if Trigger Link is the
selected Trigger-In Source. For example, if the Trigger Out Event for Measure is ON, an
output trigger will be sent after the Measure action. When used with a scanner, an output
trigger after each measurement can signal the scanner to select the next channel in the
scan.
NOTE When using SourceMeter autoranging, it is recommended that you use measure
output triggers to avoid erroneous results.
Arm Layer Output Trigger — The SourceMeter can also be programmed to output a trig-
ger when operation enters the Trigger Layer, or after operation leaves the Trigger Layer
and enters back into the Arm Layer. This output trigger is typically sent to another instru-
ment to signal the end of a scan or sweep.
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