Data Translation DT300 Series, Руководство пользователя, Страница: 99 / 164

Principles of Operation
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Figure 34 shows an example of performing an event counting operation. In this example, the
gate type is low level.
Figure 34: Example of Event Counting
Frequency Measurement
Use frequency measurement mode to measure the frequency of the signal from counter’s
associated clock input source over a specified duration. In this mode, use an external C/T
clock source; refer to
page 95 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 35 .
Figure 35: 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
STP300
Panel
TB26
Signal Source
TB25
Digital Ground
User Clock Input 0