Keithley KUSB-3116, Руководство по началу работы

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Chapter 4
46
Connecting Signals for Frequency Measurement
Operations
One way to measure frequency is to use the same wiring as a
standard event counting application that does not use a gate (see
Figure 19 on page 44 ), then use the Windows timer to determine the
duration of the frequency measurement. The frequency of the
Counter 0 Clock signal is the number of counts divided by the
duration of the Windows timer.
If you need more accuracy than the Windows timer can provide, you
can connect a pulse of a known duration (such as a one-shot output of
counter/timer 1) to the Counter 0 Gate input.
Figure 21 shows how to
connect counter/timer signals to your own screw terminal panel. In
this case, the frequency of the Counter 0 clock input is the number of
counts divided by the period of the Counter 0 Gate input signal.
Figure 21: Connecting Counter/Timer Signals to a Screw Terminal Panel for
a Frequency Measurement Operation Using an External Pulse
11
28
Counter 1 Out
8
Signal Source
Counter 0 Clock
33
Digital Ground
Screw Terminal Panel
Counter 0 Gate