Keithley 6517A, Руководство пользователя

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Front Panel Operation
2-94
The BENCH RESET condition arms the Model
6517A and places electrometer operation at point A in the
flowchart, where it is waiting for a Trigger Link trigger. Note
that since both the arm layer and scan layer are programmed
for Immediate Source, operation immediately drops down to
the measure layer at point A.
Pressing STEP takes the Model 7001/7002 out of the
idle state and places operation at point B in the flowchart.
Since both the arm layer and scan layers are programmed for
Immediate Spacing, operation drops down to the Channel
Layer at point B.
Since Channel Trigger Source is set to Source, the
scan does not wait at point B for a trigger. Instead, it bypass-
es “Wait for Trigger Link Trigger” and closes the first chan-
nel (point C). Note that the Bypass is in effect only on the
first pass through the model.
After the relay settles, the Model 7001/7002 pulls
down the Trigger Link trigger line (point D). Since the in-
strument is programmed to scan ten channels, operation
loops back up to point B, where it waits for an input trigger.
Note that Bypass is no longer in effect.
and Remember that the Model 6517A operation
is at point A waiting for a trigger. When the trigger line is
pulled low by the Model 7001/7002, the leading negative-go-
ing edge triggers the Model 6517A to measure DUT #1
(point E). Note that the electrometer holds the trigger line
low. After the measurement is complete, The Model 6517A
releases the trigger line (point F) and then loops back to point
A where it waits for another input trigger.
A
B
C
D
E F
When the Model 6517A releases the trigger line, the leading
positive-going edge triggers the Model 7001/7002 to close the
next channel in the scan. This pulls the trigger line low, trigger-
ing the Model 6517A to measure the next DUT. The process
continues until all ten channels are scanned and measured.
2.16 Buffer
The Model 6517A has a buffer to store reading data. The max-
imum possible number of stored readings depends on how
many optional data elements are selected. (Table 2-22 shows
the minimum guaranteed values of the MAX value for various
element choices.)
The basic data elements include the reading, units, reading#
and status (overflow or underflow). The reading# indicates
the location of the reading in the buffer. In addition to these
items, recalled data also includes statistical information, such
as minimum, maximum, average, and standard deviation,
which are part of the NEXT displays (see paragraph 2.16.3).
Optional data elements include timestamp, humidity, exter-
nal temperature and channel number (for scanning). When
selected, the timestamp is available on the primary display
along with the reading. If a scan was performed, the channel
number will also be displayed along with the reading if it was
selected as a data element. Humidity and external tempera-
ture are available as a NEXT display (see paragraph 2.16.3).
The following paragraphs discuss configuration of the buffer as
well as recalling buffered data. The CONFIG DATA STORE
menu structure is shown and summarized in Table 2-23.