Model 2651A High Power System SourceMeter® Instrument Reference Manual
Section 3: Functions and features
2651A-901-01 Rev. A / March 2011
3-39
SMU event detectors
As shown in the
Using the remote trigger model
(on page 3-34) topic, the source-measure unit (SMU)
has multiple event detectors (see the table below) in order to control the timing of various actions.
Each event detector monitors for the trigger event assigned to the associated stimulus input.
Operation through the trigger model is delayed at the event detector until the programmed trigger
event occurs.
If the stimulus input is set to zero (0), then the SMU continues uninterrupted through the remote
trigger model.
Event detectors
Event detector
Function
Arm
Controls entry into the trigger layer of the trigger model.
Source
Controls execution of the source action.
Measure Controls
execution
of the measurement action.
End pulse
Controls execution of the end pulse action.
Clearing SMU event detectors
When an event detector is cleared, the event detector discards previously detected trigger events.
This prevents the source-measure unit (SMU) from using trigger events that were detected during the
last sweep or while it is in the arm layer, and allows it to start monitoring for new trigger events.
SMU event detectors are automatically cleared when:
•
A sweep is initiated using the
smua.trigger.initiate()
function.
•
The SMU moves from the arm layer into the trigger layer and the
smua.trigger.autoclear
attribute is enabled.
Using the TRIG key to trigger a sweep
The source-measure unit (SMU) can be configured to perform a sweep where each source step is
triggered by the front-panel TRIG key. The source action is preceded by the source event detector
(see the following figure). The SMU pauses operation at an event detector until a programmed event
occurs. The SMU can be programmed to wait at the source event detector (that is, not start the
source action) until the front panel TRIG key is pressed.
To configure the front panel TRIG key to trigger the source action, assign the trigger event created by
the TRIG key (
display.trigger.EVENT_ID
) to the source stimulus input
(smua.trigger.source.stimulus
).
