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Owning Palette: Sound Level VIs

Installed With: Sound and Vibration Measurement Suite

Computes the exponential averaged sound level of scaled signal [EU] based on exponential mode and returns the sound level for the signal in exp avg sound level [dB EU]. The SVL Exp Avg Sound Level VI returns the exponential average sound level computed after each individual sample of the time record. The data type you wire to the scaled signal [EU] input determines the polymorphic instance to use.

Details  

Use the pull-down menu to select an instance of this VI.

Select an instance SVL Exp Avg Sound Level (1 Ch)SVL Exp Avg Sound Level (N Ch)

SVL Exp Avg Sound Level (1 Ch)

	scaled signal [EU] specifies the scaled signal expressed in the selected engineering units. To obtain a properly scaled signal, you can use the SVL Scale Voltage to EU VI or define a virtual channel in National Instruments Measurement & Automation Explorer (MAX). t0 is the start time of the waveform. dt is the time interval in seconds between data points in the waveform. Y contains the data values of the waveform.
	exponential mode specifies the exponential averaging mode. The Custom option enables you to specify any positive time constant. 0 Slow t = 1 s 1 Fast (default) t = 125 ms 2 Impulse t = 35 ms rising and 1.5 s falling 3 Custom
	time constant specifies the time constant in milliseconds used for exponential averaging if exponential mode is set to Custom. In all other cases, this parameter is ignored.
	error in describes error conditions that occur before this VI or function 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. This VI or function runs normally only if no error occurred before this VI or function runs. 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 exception control to treat what is normally an error as no error or to treat a warning as an error. 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. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	restart averaging specifies if the selected averaging process has to be restarted. The default is FALSE. When you call this VI for the first time, the averaging process restarts automatically.
	exp avg sound level [dB EU] returns the exponential averaged sound level expressed in decibels.
	unit label returns the selected engineering units.
	actual time constant [ms] returns the time constant actually used for the selected exponential averaging mode. Slow mode returns 1000 ms. Fast mode returns 125 ms. Impulse mode returns 35 ms.
	error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.
	maximum sound level [dB EU] returns the maximum value from exp avg sound level [dB EU]. The maximum value returned is the greatest value measured since averaging last restarted.

SVL Exp Avg Sound Level (N Ch)

	scaled signals [EU] specifies the scaled signals expressed in the selected engineering units. To obtain a properly scaled signal, you can use the SVL Scale Voltage to EU VI or define virtual channels in National Instruments Measurement & Automation Explorer (MAX).
	exponential mode specifies the exponential averaging mode. The Custom option enables you to specify any positive time constant. 0 Slow t = 1 s 1 Fast (default) t = 125 ms 2 Impulse t = 35 ms rising and 1.5 s falling 3 Custom
	time constant specifies the time constant in milliseconds used for exponential averaging if exponential mode is set to Custom. In all other cases, this parameter is ignored.
	error in describes error conditions that occur before this VI or function 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. This VI or function runs normally only if no error occurred before this VI or function runs. 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 exception control to treat what is normally an error as no error or to treat a warning as an error. 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. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	restart averaging specifies if the selected averaging process has to be restarted. The default is FALSE. When you call this VI for the first time, the averaging process restarts automatically.
	exp avg sound levels [dB EU] returns the exponential averaged sound levels expressed in decibels.
	unit labels returns the unit label for each channel.
	actual time constant [ms] returns the time constant actually used for the selected exponential averaging mode. Slow mode returns 1000 ms. Fast mode returns 125 ms. Impulse mode returns 35 ms.
	error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.
	maximum sound levels [dB EU] contains the maximum sound level [dB EU] for each channel. The maximum value returned is the greatest value measured since averaging last restarted.

SVL Exp Avg Sound Level Details

The SVL Exp Avg Sound Level VI returns the sound level as an array having the same size as the original time record.

The SVL Exp Avg Sound Level VI requires a continuous input data stream. An internal mechanism automatically detects any sampling discontinuity and resets the filters.