Keithley KPCI-3101 Series, User Manual

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KPCI-3101 — KPCI-3104 Series User’s Manual Installation and Configuration 3-23
Connecting frequency measurement signals
This section describes two examples of how to connect frequency measurement signals to the
STA-300 screw terminal panel.
The first configuration uses the same wiring as an event counting application that does not use an
external gate signal (see
Figure 3-15 on page 3-22 ); the software uses the Windows timer to
specify the duration of the frequency measurement. In this configuration, the frequency of the
clock input is the number of counts divided by the duration of the Windows timer.
If you need more accuracy than the Windows timer provides, you can connect a pulse of a
known duration (such as a one-shot output of another user counter) to the external gate input, as
shown in
Figure 3-17 . In this configuration, the frequency of the clock input is the number of
counts divided by the period of the external gate input.
Figure 3-17
Connecting frequency measurement signals (shown for clock input 0
and external gate 0)
Connecting pulse output signals
Figure 3-18 shows one example of connecting pulse output signals to the STA-300 screw termi-
nal panel using user counter 0.
Figure 3-18
Connecting pulse output signals (shown for counter output 0 and gate 0)
STA-300 Panel
TB26
Signal Source
TB29
TB28
Gate 0
TB31
User
Counter
Output 1
TB25
Digital Ground
User Clock Input 0
STA-300 Panel
TB27
Heater
Controller
Digital Ground
TB29
TB28
Digital Ground
Gate 0
External
Gating
Switch
TB25
User Counter Output 0