Programming instructions

Chapter 24 Generating a Square Pulse or Pulse Trains
LabVIEW Data Acquisition Basics Manual 24-12
© National Instruments Corporation
8253/54
Figure 24-15 shows how to connect your counter and device to generate a
continuous pulse train. If you use counter 0, an internal source is counted
to generate the output signal. If you use counter 1 or 2, you will need to
connect your own source to the CLK pin. You obtain the continuous pulse
train for your external device from the counter's OUT pin.
Figure 24-15.
External Connections Diagram from the Front Panel
of Cont Pulse Train (8253) VI
Figure 24-16 shows the diagram of the Cont Pulse Train (8253) VI located
in
labview\examples\daq\counter\8253.llb
. This example shows
how to use the Generate Pulse Train (8253) VI to generate a continuous
pulse train. When using
Counter 0
with this VI, you can specify the desired
frequency. The actual frequency shows the closest frequency to your
desired frequency that the counter was able to achieve. The actual duty
cycle will be as close to 0.5 as possible for your actual frequency. When
using
Counter 1
or
Counter 2
, you specify the divisor factor N to be used
to divide your supplied source. You can optionally enter the user supplied
timebase if you want the VI to calculate your actual frequency and actual
duty cycle. When the
STOP
button is pressed, the while loop stops and a
call to ICTR Control resets the counter, stopping the generation. For a
complete description of this example, refer to the information found in
Windows»Show VI Info…
.