Keithley 2790, Reference Manual

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6-2 Model 2790 SourceMeter
®
Switch System Reference manual
Buffer overview
The Model 2790 has a data store (buffer) to store from 2 to 55,000 readings. The instru-
ment stores the readings that are displayed during the storage process. Each timestamped
reading includes the buffer location number and a timestamp.
The data store also provides statistical data on the measured readings stored in the buffer.
These include minimum, maximum, average, peak-to-peak, and standard deviation.
klqb
When scanning, the readings are automatically stored in the buffer.
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The various instrument operations, including buffer operation, are performed on
the input signal in a sequential manner. See
Appendix C for details. It includes
flowcharts showing where in the processing sequence that buffer operations
occur.
Front panel buffer
Auto clear
With buffer auto clear enabled, the buffer is cleared (readings lost) before a new storage
operation starts. The buffer can be manually cleared by setting the number of readings to
store (buffer size) to 000000.
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When editing the reading count over the front panel, press AUTO to reset the
count to 000000. You can then press <ENTER> to clear the buffer.
When buffer auto clear is disabled, the buffer is not cleared and the buffer size is set to
55000. Each subsequent storage operation appends the readings to the buffer. When the
buffer fills with 55,000 readings, the storage process stops. The 55,000 readings are
cleared before the next storage operation starts.
With buffer auto clear disabled, the only two valid buffer size values are 55000 and
000000. Buffer size 000000 clears the buffer. Entering any other buffer size value resets
the buffer size to 55000.