Keithley 7001, Instruction Manual

Page: 110 / 353

Front Panel Operation
4-61
Pressing TRIG takes the meter out of the idle
state and places meter operation at point A in the flow-
chart where it is waiting for a Trigger Link trigger. Note
that since both the arm layer and scan layer are pro-
grammed for Immediate Source, operation immediate-
ly drops down to the measure layer at point A.
Pressing STEP takes the Model 7001 out of the
idle state and places operation at point B in the flow-
chart. Since both the arm and scanner layers are pro-
grammed for Immediate Spacing, immediately and
operation drops down to the channel layer at point B.
Since Channel Trigger Control is set for Source,
the scan will not wait at point B for a trigger. Instead it
will bypass “Wait for Trigger Link Trigger” and close
the first channel (point C). Note that the Bypass is only
in effect on the first pass through the model.
After the relay settles, the Model 7001 will pull
down the Trigger Link trigger line (point D). Since the
instrument is programmed to scan 10 channels, opera-
tion will loop back up to point B where it will wait for
an input trigger. Note that Bypass is no longer in effect.
A
B
C
D
& Remember that meter operation is at point
A waiting for a trigger. When the trigger line was
pulled low by the Model 7001, the leading negative-go-
ing edge triggers the meter to measure DUT #1 (point
E). Note that the meter holds the trigger line low. After
the measurement is completed, the meter will release
the trigger line (point F) and then loop back to point A
where it will wait for another input trigger.
When the meter released the trigger line, the leading
positive-going edge triggers the Model 7001 to close
the next channel in the scan which in turn pulls the
trigger line low triggering the meter to measure the
next DUT. This process continues until all 10 channels
are scanned and measured.
E F
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