Measurement Averaging VI 1.1 2004/06/17 15:45:08 GMT-5 2004/07/16 15:31:08.662 GMT-5 National Instruments certification@ni.com Elizabeth Gregory lizzardg@rice.edu Malan Shiralkar mshiralkar05@hotmail.com Harika Basana ilsai@rice.edu National Instruments certification@ni.com National Instruments LabVIEW Measurement Averaging VI exercise In this exercise, the objective is to reduce noise in analog measurements by averaging. Run the Voltmeter VI. Introduce noise into the temperature measurement by changing the Temp Sensor Noise switch on the DAQ Signal Accessory to the ON position. The measurements begin to fluctuate with noise spikes.

Block Diagram Stop the VI and display the block diagram. Modify the block diagram to calculate the average of 100 measurements.

Place the Collector Express VI located on the Functions>>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 the Configure Collector dialog box that appears, set the Maximum number of samples to 100. Click the OK button to close the dialog box. Place the Statistics Express VI, located on the Functions>>Analysis palette, on the block diagram. In the Configure Statistics dialog box that appears, place a checkmark in the Arithmetic Mean checkbox to perform averaging on the collected data. Click the OK button to close the dialog box. Select File>>Save As to save the VI as Measurement Averaging.vi in the C:\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.