Amplitude and Level Measurements Express VI

Dialog Box Options

Parameter	Description
Amplitude Measurements	Contains the following options: Mean (DC)—Acquires a DC measurement of Signals. RMS—Calculates the root mean square value of Signals. Apply window—Applies a low side lobe window to Signals. This option is available only when you place a checkmark in the DC or RMS checkbox. Use smoothing windows to taper the sharp transitions in the effective signal. You do not typically use windows if you can acquire an integer number of cycles of the signal or if you are analyzing noise spectra. Positive peak—Measures the most positive peak in Signals. Negative peak—Measures the most negative peak in Signals. Peak to peak—Measures the most positive peak to the most negative peak in Signals. Cycle average—Measures the mean level of one complete period of a periodic input signal. Cycle RMS—Calculates the root mean square value of one complete period of a periodic input signal.
Results	Displays the measurements you configured this Express VI to perform and the calculated values of those measurements. You can click any measurement listed in the Measurement column, and the corresponding value or plot appears in the Result Preview graph.
Input Signal	Displays the input signal. If you wire data to the Express VI and run it, Input Signal displays real data. If you close and reopen the Express VI, Input Signal displays sample data until you run the Express VI again.
Result Preview	Displays a preview of the measurement. The Result Preview plot indicates the value of the selected measurement with a dotted line. If you wire data to the Express VI and run the VI, Result Preview displays real data. If you close and reopen the Express VI, Result Preview displays sample data until you run the VI again. If the cutoff frequency values are invalid, Result Preview does not display valid data.

Block Diagram Inputs

Parameter	Description
Signals	Contains the input signal or signals.
error in	Describes error conditions that occur before this node runs.
Restart Averaging	Specifies whether to restart the selected averaging process. The default is FALSE. When you call this Express VI for the first time, the averaging process starts automatically. This input appears only if you place a checkmark in the Averaging checkbox.

Block Diagram Outputs

Parameter	Description
Cycle Average	Returns the mean level of one complete period of a periodic input signal. The cycle average of a perfect sine wave is zero, but the average level of the entire signal can be nonzero as a result of partial periods at the boundaries of the signal.
Cycle RMS	Returns the root mean square value of one complete period of a periodic input signal.
Mean (DC)	Returns the measured DC value of Signals.
Negative Peak	Returns a measurement of the most negative peak in Signals.
Peak to Peak	Returns a measurement from the most positive peak to the most negative peak in Signals.
Positive Peak	Returns a measurement of the most positive peak in Signals.
RMS	Returns the calculated RMS of the values in Signals.
error out	Contains error information. This output provides standard error out functionality.

This Express VI operates similarly to the following VIs and functions:

Basic Averaged DC-RMS
Averaged DC-RMS
Amplitude and Levels
Cycle Average and RMS

Example

Refer to the Express VI - Amplitude and Level Measurements VI in the labview\examples\Express VIs directory for an example of using the Amplitude and Level Measurements Express VI.

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