Programming instructions

Chapter 26 Measuring Frequency and Period
LabVIEW Data Acquisition Basics Manual 26-10
© National Instruments Corporation
DAQ-STC, Am9513
If you need more control over when period measurement begins and ends,
use the Intermediate VIs instead of the Easy VIs. Figure 26-11 shows how
to measure period and frequency.
Figure 26-11.
Measuring Period Using Intermediate Counter VIs
The Intermediate VIs used in Figure 26-11 include Pulse Width or Period
Meas Config, Counter Start, Counter Read, and Counter Stop. The Pulse
Width or Period Meas Config VI configures the counter for period
measurement. The Counter Start begins the counting operation. Counter
Read returns the count value from the counter, which is used to determine
the period and frequency.
8253/54
The 8253/54 chip does not support period measurement, but you can
use frequency measurement for a pulse train and take the inverse to get
the period. The Measure Frequency < 1 kHz (8253) VI located in
labview\examples\daq\8253.llb
measures frequency and calculates
the period for you.