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Owning Palette: Time-Domain Measurements Express VIs

Installed With: Sound and Vibration Measurement Suite

Performs sound level measurements, including linear, exponential, and peak hold averaging for a single channel or N channels. You also can apply A-, B-, or C-weighting to the time-domain signals.

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Dialog Box Options

Parameter	Description
View	Specifies the display that appears in the Signals graph.
Signals	Displays the input signals or the weighted signals. Use the Zoom button to zoom in and out of the display. Select the display you want to view from the View pull-down menu.
Autoscale	Automatically adjusts the scales of the graph to display the data.
Sound levels	Displays the results of the sound level measurements selected using the Weighting and Averaging mode. This table also displays the units of the sound level measurements. You can replace the Signals graph with a larger Sound levels table by selecting Results Table from the View pull-down menu.
Input	Specifies whether to operate on a single channel or on N channels. This option is available only with the NI Sound and Vibration Assistant. Input signal—Configures the measurement for a single channel or N channels. Changing this selection changes the data types of the input signals and computed measurements.
Weighting	Configures the weighting applied before the sound level measurements. Weighting—Specifies one of the following types of weighting: Linear (Default)—Applies no weighting to the input signals. A Weighting—Applies A-weighting to the input signals. B Weighting—Applies B-weighting to the input signals. C Weighting—Applies C-weighting to the input signals. Export weighted signal—Exports the weighted signal by creating a weighted signals output. If you select Linear for the Weighting, the input signal is exported as the output.
Averaging	Specifies the averaging parameters. Averaging Mode—Specifies which type of sound level measurements to compute. The results appear in the Sound levels table. Leq—Computes the equivalent continuous sound level (Leq) of the weighted signals. Running Leq—Computes the running Leq level of the weighted signals. Peak—Computes the peak level of the weighted signals. Exponential—Computes the exponential averaged sound level of the weighted signals. Running Leq Averaging—Specifies the parameters for computing the running equivalent continuous sound level (Leq) of the weighted signals. Integration time (s)—Specifies the duration over which the running Leq computation occurs, in seconds. The duration might be rounded to a duration corresponding to an integer multiple of the duration of a single block of time-domain data. Exponential Averaging—Specifies the parameters for exponential averaging. Mode—Specifies the exponential averaging mode with the following options: Slow—time constant = 1 s Fast (Default)—time constant = 125 ms Impulse—time constant = 35 ms rising and 1.5 s falling Custom—Any strictly positive Time constant (s) Time constant (s)—Specifies the time constant in seconds used for exponential averaging if you set Mode to Custom.

Block Diagram Inputs

Parameter	Description
input signals	Specifies the input signals.
error in	Describes error conditions that occur before this Express VI runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
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 restarts automatically.

Block Diagram Outputs

Parameter	Description
weighted signals	Returns the weighted signals. This output is available only when you place a checkmark in the Export weighted signal checkbox.
Leq	Returns the Leq sound levels.
exponential	Returns the exponential sound levels.
peak	Returns the peak sound levels.
running Leq	Returns the running Leq sound levels.
unit labels	Returns the unit labels.
error out	Contains error information. This output provides standard error out functionality.