Keithley 2657A, Reference Manual, Page: 158 / 805

Section 3: Functions and features Model 2657A High Power System SourceMeter® Instrument Reference Manual
3-44 2657A-901-01 Rev. B/December 2012
Figure 46: Using a timer for an SDM cycle
Timer action overruns
The timer generates an action overrun when it is triggered while a timer delay is still in progress. Use
the status model to monitor for the occurrence of action overruns (for details, see the
Status model
(on page E-1)).
Using timers to perform pulse mode sweeps
Timers can also be used to control the pulse width during a pulsed sweep. To create a pulse train, a
second timer must be used to configure the pulse period. The examples below show a single pulse
output and a pulse train output.
The SMU end pulse action
smua.trigger.endpulse.action
must be set to
smua.SOURCE_IDLE
in order to create a pulse.
Single pulse example:
The programming example below illustrates how to use a single timer to control the pulse width of a
single-shot pulse measurement. The programming example configures the timer and SMU as follows:
Timer 1: Pulse width timer
•
Set the delay attribute of a timer equal to the appropriate pulse width.
•
Configure the timer to trigger when the SMU moves out of the arm layer of the trigger model.
•
Assign the trigger event generated by the timer to the stimulus input of the SMU end pulse event
detector.
SMU A
•
Configure the source action to start immediately by setting the stimulus input of the source event
detector to 0.
•
Set the end pulse action to
SOURCE_IDLE.
Stimulus input:
trigger.timer[1].stimulus
SMU A
Timer
#1
Trigger event:
smua.trigger.SOURCE_COMPLETE_EVENT_ID
Trigger event:
trigger.timer[1].EVENT_ID
Stimulus input:
smua.trigger.measure.stimulus
Legend:
= Trigger object
= Trigger events
= Stimulus input
NOTE