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Owning Palette: Time-Domain Measurements Express VIs

Installed With: Sound and Vibration Measurement Suite

Performs several vibration level measurements for a single channel or N channels. You also can perform single or double integration on the time-domain signal. You can compute the velocity or the displacement from an acceleration measurement.

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 integrated 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.
Vibration levels	Displays the results of the vibration level measurements selected using the Averaging mode. This table also displays the units of the vibration level measurements. You can replace the Signals graph with a larger Vibration 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.
Integration	Configures the integration applied before the vibration level measurements. Integration type—Specifies one of the following integration types: None (Default)—Applies no integration to the input signals. Single Integration—Applies single integration to the input signals. Double Integration—Applies double integration to the input signals. Export integrated signal—Exports the integrated signal by creating an integrated signals output. If you select None for the Integration type, the Input signal is exported as the output.
Averaging	Specifies the averaging parameters. Averaging Mode—Specifies which type of vibration level measurement to compute. The results appear in the Vibration levels table. All measurements operate on the integrated signals. RMS—Computes the root-mean-square (RMS) level. Peak—Computes the peak level (maximum of absolute values) of the integrated signals. Exponential—Computes the exponential average level. Running RMS—Computes the running RMS level. Max-Min—Computes the difference between the maximum and minimum levels. Running RMS Averaging—Specifies the running RMS level parameters. Integration time (s)—Specifies the duration over which the running RMS 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
integrated signals	Returns the integrated signals. This output appears only when you place a checkmark in the Export integrated signal checkbox.
RMS	Returns the root-mean-square (RMS) vibration levels.
running RMS	Returns the running RMS vibration levels.
exponential	Returns the exponential average vibration levels.
peak	Returns the peak vibration levels.
max-min	Returns the difference between the maximum and minimum vibration levels.
unit labels	Returns the unit labels.
error out	Contains error information. This output provides standard error out functionality.