Connecting Frequency Measurement Signals - Measurement Computing Data Translation DT3010 Series User Manual

Signal
Source
External
Gating
Switch
Figure 42: Cascading Counters on an STP268-EC Screw Terminal Panel
(Shown for Event Counting Using Counters 0 and 1 and External Gate 0)

Connecting Frequency Measurement Signals

You can connect a frequency measurement application to a DT740 or STP268 screw terminal
panel in two ways.
The first configuration uses the same wiring as an event counting application that does not
use an external gate signal (see
the STP268, or Figure 41 on page 82
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.
In this configuration, the frequency of the clock input is the number of counts divided by the
period of the external gate input. For an example of this configuration, refer to
the DT740, Figure 44
Digital Ground
User Clock Input 0
Digital Ground
Gate 0
Note that you can internally cascade counters using software; if you
internally cascade the counters, you do not have to make the
external cascading connections. Note also that this example shows
the use of an external gate; however, this connection is not required.
Figure 35 on page 78
for the STP268-EC). The software uses the Windows timer
for the STP268, or Figure 45
STP268-EC Panel
Gate 1
TB3
TB4
User
Clock
TB5
Output 0
for the DT740, Figure 38
for the STP268-EC.
Wiring Signals
TB35
TB36
TB37
TB38
User
Clock
Input 1
on page 80 for
Figure 43 for
83