Keithley 2790, Reference Manual

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13-6 Model 2790 SourceMeter
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FETCh?
Description
This command requests the latest post-processed reading. After sending
this command and addressing the Model 2790 to talk, the reading is sent
to the computer. This command does not affect the instrument setup.
This command does not trigger a measurement. The command simply
requests the last available reading.
FETCh? can also be used to return more than one reading. When return-
ing more than one reading, the readings are automatically stored in the
buffer.
In order to return multiple reading strings, continuous initiation must be
disabled (INIT:CONT OFF) so that the sample count
(SAMPle:COUNt), which specifies the number of measurements to be
performed, can be set >1. After INITiate is sent to trigger the measure-
ments, FETCh? will return the reading strings.
FETCh? is automatically asserted when the READ? or MEASure? com-
mand is sent.
klqb
FETCh? can repeatedly return the same reading. Until there is a new reading,
this command continues to return the old reading.
When an instrument setting that is relevant to the readings in the sample buffer
is changed, the FETCh? command will cause error -230 (data corrupt or stale)
or a bus time-out to occur. To get FETCh? working again, a new reading must
be triggered.