Keithley KPCI-3101 Series, Руководство пользователя

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2-24 Principles of Operation KPCI-3101 — KPCI-3104 Series User’s Manual
Figure 2-11 shows an example of performing an event counting operation. In this example, the
gate type is low level.
Figure 2-11
Example of event counting
Frequency measurement
Use frequency measurement mode to measure the frequency of the signal from counter’s associ-
ated clock input source over a specified duration. In this mode, use an external C/T clock source;
refer to
page 2-20 for more information on the external C/T clock source.
One way to perform a frequency measurement is to use the same wiring as an event counting
application that does not use an external gate signal, as shown in
Figure 2-12 .
Figure 2-12
Connecting frequency measurement signals without an external gate input
(shown for clock input 0)
Gate Input
Signal 0
Low Level
Enables Operation
High Level
Disables Operation
External C/T
Clock 0
Input Signal
Event Counting
Operation Starts
Event Counting
Operation Stops
3 events are counted while
the operation is enabled
STA-300
Panel
TB26
Signal Source
TB25
Digital Ground
User Clock Input 0