You are here: NI Home > Support > Product Reference > Manuals > Sound and Vibration Measurement Suite 7.0 Help

Owning Palette: Sound Level VIs

Installed With: Sound and Vibration Measurement Suite

Allows you to compute several sound level measurements including equivalent continuous level (Leq), running Leq level, exponential averaged level, and/or the peak level of scaled signal [EU]. 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 SVT Sound Level (1 Ch)SVT Sound Level (N Ch)

SVT Sound Level (1 Ch)

	integration time specifies the duration, in seconds, over which the running Leq is computed. integration time is rounded to a duration corresponding to an integer multiple of the duration of a single block of time-domain data.
	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.
	measurement selection specifies the desired types of sound level measurements. Leq specifies if the VI computes the equivalent continuous sound level (Leq) of scaled signal. The default is TRUE. Running Leq specifies if the VI computes the running equivalent continuous sound level (Leq) of scaled signal. The default is FALSE. Exponential specifies if the VI computes the exponential averaged sound level of scaled signal based on exponential mode. The default is FALSE. Peak specifies if the VI computes the peak sound level of scaled signal. The default is FALSE.
	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.
	Leq sound level [dB EU] returns the equivalent continuous sound level (Leq) expressed in decibels.
	running Leq sound level [dB EU] returns the running equivalent continuous sound level (Leq) in decibels.
	peak sound level [dB EU] returns the peak sound level expressed in decibels.
	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.
	unit label returns the selected engineering units.

SVT Sound Level (N Ch)

	integration time specifies the duration, in seconds, over which the running Leq is computed. integration time is rounded to a duration corresponding to an integer multiple of the duration of a single block of time-domain data.
	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 a virtual channel in National Instruments Measurement & Automation Explorer (MAX).
	measurement selection specifies the desired types of sound level measurements. Leq specifies if the VI computes the equivalent continuous sound level (Leq) of scaled signal. The default is TRUE. Running Leq specifies if the VI computes the running equivalent continuous sound level (Leq) of scaled signal. The default is FALSE. Exponential specifies if the VI computes the exponential averaged sound level of scaled signal based on exponential mode. The default is FALSE. Peak specifies if the VI computes the peak sound level of scaled signal. The default is FALSE.
	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.
	Leq sound levels [dB EU] returns the equivalent continuous sound levels (Leq) expressed in decibels.
	running Leq sound levels [dB EU] returns the running equivalent continuous sound levels (Leq) in decibels.
	peak sound levels [dB EU] returns the peak sound level expressed in decibels.
	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.
	unit labels returns the unit label for each channel.

SVT Sound Level Details

Each measurement is returned as a waveform. Use t0 from the waveform as the start time for the measurement.

exp avg level has been decimated already to reduce the number of level measurement to log, process, and display.