Keithley 2790, Reference Manual

Page: 222 / 568

Model 2790 SourceMeter
®
Switch System Reference Manual 7-17
3. If you did not disable the channel, make your setup changes (if any) for the
selected function. These changes do not affect the following channels.
4. Using the or key or the CLOSE key to select the channel, repeat steps 2-2
and 2-3 to set other channels.
5. When finished setting up channels, press ENTER to proceed to set up triggering.
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If there are not at least two channels in the scan list (two or more channels
enabled), the message “INVALID LIST” will appear briefly. You will not be able
to exit from the scan configure menu or finish the scan setup until you enable at
least two channels.
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The remaining steps are used to check or change the setups for triggering, timer,
and reading count. If you are not going to make changes to any of those setups,
you can exit from the scan setup menu by pressing EXIT twice. The instrument
returns to the normal measurement mode.
Step 3: Enable immediate scan
The present state of immediate scan (IMM SCAN) is displayed: Y (yes, which is the fac-
tory and *RST default) or N (no). With immediate scan enabled, the scan will start when
you press the STEP or SCAN key. Use the
or key to display IMM SCAN: Y and
press ENTER.
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Disable immediate scan (IMM SCAN: N) when you wish to use a monitored
reading limit to trigger the start of the scan. This technique to start a scan is
covered later in this section. See
“Scan operation (7702 only)” page 7-21 .
Step 4: Timer controlled scan
The present state of the TIMER will be displayed: NO or YES. If you do not wish to use
the timer, use the
or key to display TIMER? NO (which is the factory and *RST
default) and press ENTER.
To use the timer, use the or key to display TIMER? YES and press ENTER. The timer
interval is displayed in the hour/minute/second format. The timer can be set from 0.001 sec
(00H:00M:00.001S) to 99 hr, 99 min, 99.999 sec (99H:99M:99.999S). Note that pressing the
AUTO key sets the timer to 0.001 sec. With the desired interval displayed, press ENTER.
Step 5: Set the reading count
The displayed reading count (RDG CNT) sets the number of channels to scan (STEP) or
the number of scans to run (SCAN). You can change the reading count to any finite value
from 2 to 55000 or you can select infinite (continuous scanning). To select infinite, set the
reading count to 00000 to display INF. With the desired reading count setting displayed,
press ENTER. The instrument returns to the normal measurement mode.
See “Trigger models” page 7-4 , for details on reading count.