Keithley 2651A Reference Manual page 171

Section 3: Functions and features
Output characteristics:
•
In addition to trigger events from other trigger objects, the digio.trigger[N].assert() and
tsplink.trigger[N].assert() functions generate a low pulse for the programmed pulse
duration if the line is latched low, a falling edge does not occur.
•
A normal falling edge pulse generates when the internal drive is not latched low and the
digio.trigger[N].assert() and tsplink.trigger[N].assert() functions are issued.
•
To mirror the SynchronousA trigger mode, set the pulse width to 1 μs or any small nonzero value.
•
Action overruns are disabled.
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Model 2651A High Power System SourceMeter® Instrument Reference Manual
Figure 63: Synchronous input trigger
External Drive
Internal Drive
Physical Line State
Event
Stimulus Event
Action Overrun
Figure 64: Synchronous output trigger
External Drive
Internal Drive
Physical Line State
Event
Stimulus Event
Action Overrun
Pulse Width
Input Trigger
Pulse Width
Output Triggers
2651A-901-01 Rev. A / March 2011