Keithley 2700, User Manual, Page: 223 / 500

7-10 Scanning Model 2700 Multimeter/Switch System User’s Manual
SCAN operation
— When a scan is started, one or more complete scans will be
performed. The number of channels in the scan list determines the number of channels for
each scan. The reading count determines the number of scans to perform and is best
explained by an example. Assume there are 10 channels in the scan list. If you set the
reading count to 10 or less, one scan of the 10 channels will be performed. If you set the
reading count to any value from 11 to 20, two scans will be performed. A reading count
from 21 to 30 gives you three scans, and so on.
If the reading count is set to infinity (INF), the scan will continuously repeat until you
stop it.
NOTE
As shown in Figure 7-2 , two counters are used for SCAN operation. The Trigger
counter controls the number of scans, and the Sample Counter controls the
number of channels for each scan. The number of channels in the scan list and
the programmed reading count automatically sets the Trigger Counter and the
Sample Counter.
The Sample Count is equal to the scan list length. For example, if channels 101,
102, and 103 are programmed to be scanned, the Sample Count is 3.
Output trigger
STEP operation
— After each channel is scanned, an output trigger is applied to the rear
panel Trigger Link connector.
SCAN operation
— After all channels in the scan list are scanned, an output trigger is
applied to the rear panel Trigger Link connector.
Scan configuration
A scan is configured from the scan configuration menu which is accessed by pressing
SHIFT and then CONFIG.
Figure 7-3 shows the basic flowchart to configure a scan. After
entering the menu structure you can configure a simple scan, an advanced scan, or reset
the configuration to the default setup for a simple scan. Refer to the flowchart in
Figure 7-3 for the following discussions on “ Scan reset ,” “ Simple scan ,” and “ Advanced
scan .”
NOTE
Only a sequential scan can be configured from the front panel. For a sequential
scan, the scan proceeds from the lowest numbered channel to the highest.
Non-sequential (backward) scanning is only intended to be performed using
remote programming. Unexpected results may occur if a non-sequential scan is
run from the front panel.
For more information, see “ Scanning fundamentals — Sequential and non-
sequential scans,” page 7-3 .