Data Translation DT300 Series, User Manual

Page: 55 / 164

Wiring Signals
55
Connecting Frequency Measurement Signals
This section describes two examples of how to connect frequency measurement signals to the
STP300 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 18 on page 54 ); 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 20 . In this configuration, the frequency of the clock input is the number of
counts divided by the period of the external gate input.
Figure 20: Connecting Frequency Measurement Signals
(Shown for Clock Input 0 and External Gate 0)
STP300 Panel
TB26
Signal Source
TB29
TB28
Gate 0
TB31
User
Counter
Output 1
TB25
Digital Ground
User Clock Input 0