Keithley 2303, Руководство пользователя

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Long Integration Measurements 4-3
Integration time
The integration time period can be set automatically or manually by the user. The integration
time can be as long as 60 seconds. For 60Hz power line frequency, the minimum integration time
setting is 850msec. For 50Hz power line frequency, the minimum integration setting is 840msec.
Use AUTO TIME when you want to perform a long integration measurement of each pulse.
When the AUTO TIME operation is performed, the instrument measures the time between two
rising pulse edges and sets an appropriate integration time that will encompass the high and low
periods of the pulse. This integration time applies for all subsequent long integration measure-
ments until another AUTO TIME is performed or the time is changed manually.
If you want the integration period to encompass two or more pulses, you will have to set the
integration time manually. However, you must make sure that the integration period does not
extend into a pulse that you do not want measured. For example, if you want a long integration
of two pulses, you must make sure that the set integration time does not extend into the third
pulse.
Trigger edge
A pulse edge can be used to trigger the start of the measurement. Either a RISING pulse edge
or a FALLING pulse edge can start the measurement. A third option is available if you do not
want measurements controlled by pulse edges. With NEITHER selected, measurements start as
soon as the long integration function is selected.
A pulse has to be detected before a RISING or FALLING pulse edge can trigger a long inte-
gration measurement. All pulses that are less than the specified trigger level are ignored (see
“Trigger level”). Pulse edges are ignored while a long integration is in process. No pulse detec-
tion is needed if NEITHER trigger edge is selected.
Trigger level
Before a rising or falling pulse edge can trigger the start of a long integration, the pulse must
first be detected. Trigger level specifies the minimum pulse level that will cause detection. For
example, if the trigger level is set for 2A, pulses that are (
≥
2A will be detected. Current pulses
<2A are ignored.
For Models 2303 and 2303B, the maximum trigger level is 5A. For Model 2303-PJ, the trig-
ger level can be set for each measurement range. For the 5A range the maximum trigger level is
5A, and for the 500mA range, the maximum trigger level is 500mA.