Keithley 2302 Instruction Manual page 101

Figure 4-2
Long integration, search, and reading time comparison
Summarizing
1.
2.
3.
NOTES
PULSE TIMEOUT applies only to long integration measurements that are configured to be
triggered by rising or falling pulse edges. After the long integration function is selected, the
instrument searches for a pulse. If a pulse is not detected within the specified time (PULSE
TIMEOUT), the "NO PULSE" message will be displayed. While the "NO PULSE" message is
displayed, the instrument continues to search for a pulse. With a long timeout setting, the
instrument may appear locked up while it is searching for the pulse to start the long integration.
PULSE TIMEOUT can be set from 1.000 to 63.000 seconds.
With neither trigger edge selected, pulse timeout is not used and a pulse search is not con-
ducted. Therefore, the "NO PULSE" message is never displayed. Measurements start as soon as
the long integration function is selected, even if no pulse is present. It is the responsibility of the
user to determine if a pulse was present when the measurement was made.
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TOUT
A
Search time
Long integration
time
Figure 4-2:
Reading begins searching for high pulse at point (A).
Earliest pulse detected at point (B).
Reading time equals Long integration time.
• If a pulse is not present, timeout needs to elapse (TOUT) before "NO PULSE"
appears on the display.
• Search Time needs to elapse when checking TLEV command for valid setting.
Long Integration Measurements
B
Reading
time
4-5