Summary: In this exercise, the objective is to reduce noise in analog measurements by averaging.
EXERCISE 1
- Run the Voltmeter VI.
- Introduce noise into the temperature measurement by changing the
Temp Sensor Noise
switch on the DAQ Signal Accessory to theON
position. The measurements begin to fluctuate with noise spikes.
1.A) Block Diagram
- Stop the VI and display the block diagram. Modify the block diagram to calculate the average of 100 measurements.
Figure 1 - Place the
Collector
Express VI located on theFunctions>>Signal Manipulation
palette, on the block diagram. This Express VI creates an internal buffer to store the individual points. When the maximum number of input points is collected, the Express VI discards the oldest points and adds the newest points. In theConfigure Collector
dialog box that appears, set theMaximum number of samples
to100
. Click theOK
button to close the dialog box. - Place the
Statistics
Express VI, located on theFunctions>>Analysis
palette, on the block diagram. In theConfigure Statistics
dialog box that appears, place a checkmark in theArithmetic Mean
checkbox to perform averaging on the collected data. Click theOK
button to close the dialog box. - Select
File>>Save As
to save the VI asMeasurement Averaging.vi
in theC:\Exercises\LabVIEW Basics I
directory. - Display the front panel and run the VI. Notice that the noise spikes are reduced when the
Temp Sensor Noise
switch is turned on. - Stop and close the VI.
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