ISE 370: Industrial Automation - Binghamton



ISE 370 Industrial Automation

LabVIEW Problems

1) Create an one dimensional array of 175 random numbers 225 Signal Analysis sub-palette to create an output signal. (See the Configure Simulate Signals dialog box on back). This VI is a powerful computational method that can used to perform a spectral analysis on discrete sampled data such as that from a DAQ system.

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Place the Spectral Measurements Express VI, located on the Functions>>Signal Analysis sub-palette on the BD. The VI computes the power spectrum of a signal.

The Configure dialog box for this VI contains:

Power Spectrum under type of Measurement.

Result >> Linear

Window >> Hanning

Place the “Unbundle by Name” function & “Or” function on the BD. This returns the error status Boolean value if an error occurs to stop the While loop.

Your Power Spectrum display is a Waveform graph.

Your Sine display is a chart.

Note: Windowing is used to reduce the amplitude of the discontinuities at the boundaries of each period.

7. (Digital Filters) Digital filters can be implemented in software and are often more stable and predictable than analog filters because they do not drift with changes in external environmental conditions. One main use of filters is to remove unwanted noise from a signal. A lowpass filter passes low frequencies and attenuates high frequencies.

Build an express filter VI for filtering of a sinusoidal signal configured to provide sine wave signals at frequencies 2, 10, and 50 Hz. Use three Simulate Signal Express VI’s to produce one sinusoidal signal which represents a sum of the three individual signals. Also, provide a display of all three signals merged onto one waveform graph. This graphically displays the impact of the three sine signals summed together.

Use the Filter Express VI to provide a lowpass filter with a cutoff frequency of 20 Hz. Use a numeric control to vary the cutoff frequency directly from the front panel. Use the Spectral Measurement Express VI to provide power spectral (frequency) densities for both unfiltered and filtered signals. Use waveform graphs to display filtered and unfiltered sinusoidal signals for both the time and power spectral (frequency) density domains. Run and explain. Change the cutoff freq.

Configure the Spectral Measurement Express VI as “Power Spectral Density” for Selected Measurement, “None” for Window type, and “Linear” for Result.

Configure the Filter Express VI for “Lowpass” for the Filtering Type.

Configure the Simulate Signal Express VI’s for “Sine” for Signal type. Adjust the Frequency for 2, 10, or 50 Hz.

Use Waveform Graphs to display signals:

>> Merged Signals

>> Unfiltered Sum Signal

>> Filtered Sum Signal

>> Spectual Sum Original

>> Spectual Sum Filtered

8. (One-way ANOVA) Four different types of solar energy collectors were tested. Each was tested at five randomly chosen times, and the power (in watts) was measured. The results are shown in the table below:

Collector Power

A 1.9 1.6 2.0 1.8 1.6

B 1.7 1.9 1.8 1.7 1.7

C 1.2 0.9 1.2 0.9 1.4

D 1.5 1.0 1.4 1.3 1.4

Build an One-way ANOVA VI that will test that the mean power differs for the different collectors. Use α = 0.05. (Use the 1D ANOVA VI).

On the Front Panel provide:

>> User abliity to input a numerical value for alpha.

>> msa (MSTr)

>> MSE

>> F-calc

>> sig A (P-value)

>> Decision to Accept the Null or Alternative Hypothesis.

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