Programming instructions

Chapter 24 Generating a Square Pulse or Pulse Trains
© National Instruments Corporation 24-23 LabVIEW Data Acquisition Basics Manual
Stopping Counter Generations
You can stop a counting operation in several ways. You can restart a
counter for the same operation it just completed, you can reconfigure it to
do something else, or you can call a specific VI to stop it. All of these
methods allow you to use counters for different operations without
resetting the entire board.
DAQ-STC, Am9513
Figure 24-28 shows how to stop a counter using the Intermediate VI,
Counter Stop. Notice that the Wait+ (ms) VI is called before Counter Stop.
The Wait+ (ms) VI allows you to wire a time delay so that the previous
counter operation has time to complete before the Counter Stop VI is
called. The Wait+ (ms) and Counter Stop VIs are located in
Functions»Data Acquisition»Counter»Intermediate Counter
.
Figure 24-28.
Using the Generate Delayed Pulse and Stopping the Counting Operation
To stop a generated pulse train, another Generate Pulse Train VI can
be used with the number of pulses input set to –1. Figure 24-29 shows
an example of this. This example expects that a pulse train is already
being generated. The call to Generate Pulse Train VI stops the counter,
and the call to Generate Delayed Pulse VI sets the counter up for a
different operation.
Figure 24-29.
Stopping a Generated Pulse Train
8253/54
Calling ICTR Control VI with a control code of 7 (reset) can stop a counter
on the 8253/54 chip. Examples are shown in Figures 24-9 and 24-23.