Performs voltage measurements on a signal.


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Dialog Box Options

Option 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.

Inputs/Outputs

  • cbool.png 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.

  • cerrcodeclst.png error in (no error) —

    Describes error conditions that occur before this node runs.

  • cexpdynwdt.png Signals —

    Contains the input signal or signals.

  • iexpdynwdt.png Mean (DC) —

    Returns the measured DC value of Signals.

  • iexpdynwdt.png Negative Peak —

    Returns a measurement of the most negative peak in Signals.

  • iexpdynwdt.png 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.

  • iexpdynwdt.png Positive Peak —

    Returns a measurement of the most positive peak in Signals.

  • iexpdynwdt.png RMS —

    Returns the calculated RMS of the values in Signals.

  • iexpdynwdt.png Cycle RMS —

    Returns the root mean square value of one complete period of a periodic input signal.

  • ierrcodeclst.png error out —

    Contains error information. This output provides standard error out functionality.

  • iexpdynwdt.png Peak to Peak —

    Returns a measurement from the most positive peak to the most negative peak in Signals.

    • 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

    Examples

    Refer to the following example files included with LabVIEW.

    • labview\examples\Express VIs\Express VI - Amplitude and Level Measurements.vi