Model 2651A High Power System SourceMeter® Instrument User's Manual Section 5: Capturing high power pulse waveforms
Figure 14: Trigger model configuration for fast ADC example
Idle
Arm layer
Trigger layer
smua.trigger.
arm.count = 1
count = 5
IDLE_EVENT_ID
SWEEPING_EVENT_ID
SWEEP_COMPLETE_EVENT_ID
ARMED_EVENT_ID
SOURCE_COMPLETE_EVENT_ID
MEASURE_COMPLETE_EVENT_ID
PULSE_COMPLETE_EVENT_ID
arm.stimulus
source.stimulus
measure.stimulus
endpulse.stimulus
trigger.timer[1].
EVENT_ID
passthrough = true
count = 4
stimulus
Model 2651A
Local node*
* Local node: Since only one instrument is being used in this example, the local node is used.
trigger.timer[2].
EVENT_ID
passthrough = false
count = 1
stimulus
3 ms
0.03 s
In this example, timer 1 is used to control the time between pulses while timer 2 is used to control the
pulse width. Timer 1 also controls the start of the measurements, starting them at the same time it
triggers the pulse and thus overlapping the measurements with the pulse.
When the trigger model of the Model 2651A is initialized, the following occurs:
1. The source-measure unit (SMU) trigger model:
•
Leaves the idle state
•
Flows through the Arm Layer
•
Enters the Trigger Layer
•
Outputs the ARMED event trigger
•
Pauses at the Source Event, where it waits for an event trigger
2. Timer 1 receives the ARMED event trigger and begins its countdown while passing the event
trigger through to both the SMU's Source Event and Measure Event simultaneously.
3. The SMU Measure Event receives the event trigger from timer 1 and begins to take
measurements. Because measurements have been configured to be asynchronous, the Measure
Event begins its execution before the Source Event has completed and will continue to take
measurements even after the End Pulse Event has executed. For more information, see "Using
the remote trigger model" in the Model 2651A Reference Manual.
4. The SMU Source Event receives the event trigger from timer 1, begins to output the pulse, and
then waits the programmed source delay (if any) before it outputs the SOURCE_COMPLETE
event to timer 2 and allows the SMU trigger model to continue.
2651A-900-01 Rev. A / March 2011
5-3
