Keithley 2790, Reference Manual

Page: 226 / 568

Model 2790 SourceMeter
®
Switch System Reference Manual 7-21
Auto scan
When auto scan is enabled, the scan operation is saved in memory. If power to the
Model 2790 is interrupted, the scan will resume when power is restored. With auto scan
enabled, the last scan setup becomes the power-on setup. It takes precedence over the fac-
tory or *RST.
Perform the following steps to set auto scan.
1. While in the normal measurement state, press SHIFT and then SETUP.
2. Use the and keys to display the auto scan (AUTOSCAN) setting: N (no) or Y
(yes).
3. To change the setting, press to place the cursor on the setting (N or Y) and press
or to change the setting.
4. Press ENTER to exit from the menu structure.
klqb
If during the power-up sequence the Model 2790 detects a card ID change for
any slot, auto scan configuration will disable and an interrupted scan will not be
resumed. Error +517 occurs (cannot resume scan) to indicate that the scan has
been disabled. The instrument assumes the normal power-on setup.
Scan operation (7702 only)
A basic scan is controlled solely by the STEP and SCAN keys. When one of these keys is
pressed, the STEP or SCAN operation will be performed. For the manual/external trigger
scan, the TRIG key or triggers received from another instrument starts the STEP or SCAN
operation. For the monitor scan, a channel monitors readings. When a set reading limit is
reached, STEP or SCAN will start.
Basic scan
Perform the following steps to run the presently configured scan:
1. To start the scan, press STEP or SCAN.
2. The STEP or SCAN annunciator turns on and channels are scanned from the low-
est to highest number channel. Channels that are turned off will not be scanned.
3. Keep in mind that the Timer Delay for STEP occurs between channels, while the
Timer Delay for SCAN occurs between scans. If the timer is off, both scans will
run at virtually the same speed.
4. With reading count set to a finite value, the last channel scanned will open and the
first channel in the scan list will close. Keep in mind that the scan is still enabled
(STEP or SCAN annunciator on). When you press STEP or SCAN, the scan will
continue starting with the next channel.