Owning Palette: Waveform Measurements VIs
Requires: Full Development System
Returns the average and RMS levels of a selected cycle of a periodic waveform or an array of periodic waveforms. Wire data to the signal in input to determine the polymorphic instance to use or manually select the instance.
Note The terminology and measurement definitions for this VI comply with IEEE Standard 1812003, IEEE Standard on Transitions, Pulses, and Related Waveforms. 
Use the pulldown menu to select an instance of this VI.
cycle number specifies the cycle, or period, of the periodic signal on which to perform the measurement.  
signal in is the waveform to measure. Each waveform is required to contain at least cycle number complete cycles, where a cycle is defined as the interval between two consecutive rising mid ref level crossings.  
reference levels specifies the high, middle, and low reference levels of a waveform. LabVIEW uses the reference levels to define the measurement interval of one complete cycle. The distance between the mid ref level and the high ref level must equal the distance between the low ref level and the mid ref level. If the two distances are not equal, LabVIEW adjusts either the high ref level or the low ref level to match the smaller of the two distances. For example, if you specify a high ref level of 90%, a mid ref level of 50%, and a low ref level of 20%, LabVIEW uses 80% instead of 90% for the high ref level.
 
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.  
percent level settings specifies the method LabVIEW uses to determine the high and low state levels of a waveform. If you select percent ref units, percent level settings determines the reference levels. Otherwise, LabVIEW ignores this input.
 
cycle average is the mean level of one complete period of a periodic input waveform. The average is computed by the following equation.
where i indicates the waveform samples that fall in the single period specified by cycle number and numPoints is given by the following equation.
numPoints = int(period/dt + .5) where dt is the time between two samples and int( ) is a function that returns the integer portion of a floatingpoint number.The cycle average of a perfect sine wave is zero, while the average level of the entire waveform can be nonzero due to partial periods at the boundaries of the waveform. 

cycle RMS is the root mean square value of one complete period of a periodic input waveform. The RMS value is computed by the following equation.
where i indicates the waveform samples that fall in the single period specified by cycle number and numPoints is given by the following equation.
numPoints = int(period/dt + .5) where dt is the time between two points and int( ) is a function that returns the integer portion of a floatingpoint number. 

error out contains error information. This output provides standard error out functionality.  
measurement info returns the measurement cycle interval endpoints and the absolute reference levels used to define the measurement cycle.

cycle number specifies the cycle, or period, of the periodic signal on which to perform the measurement.  
signal(s) in is an array of waveforms containing the signals to measure. Each waveform is required to contain at least cycle number complete cycles, where a cycle is defined as the interval between two consecutive rising mid ref level crossings.  
reference levels specifies the high, middle, and low reference levels of a waveform. LabVIEW uses the reference levels to define the measurement interval of one complete cycle. The distance between the mid ref level and the high ref level must equal the distance between the low ref level and the mid ref level. If the two distances are not equal, LabVIEW adjusts either the high ref level or the low ref level to match the smaller of the two distances. For example, if you specify a high ref level of 90%, a mid ref level of 50%, and a low ref level of 20%, LabVIEW uses 80% instead of 90% for the high ref level.
 
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.  
percent level settings specifies the method LabVIEW uses to determine the high and low state levels of a waveform. If you select percent ref units, percent level settings determines the reference levels. Otherwise, LabVIEW ignores this input.
 
cycle average is an array containing the cycle average of each waveform in signal(s) in. cycle average is the mean level of one complete period of a periodic input waveform. The average is computed by the following equation.
where i indicates the waveform samples that fall in the single period specified by cycle number and numPoints is given by the following equation.
numPoints = int(period/dt + .5) where dt is the time between two samples and int( ) is a function that returns the integer portion of a floatingpoint number.The cycle average of a perfect sine wave is zero, while the average level of the entire waveform can be nonzero due to partial periods at the boundaries of the waveform. 

cycle RMS is an array containing the cycle RMS value for each waveform in signal(s) in. cycle RMS is the root mean square value of one complete period of a periodic input waveform. The RMS value is computed by the following equation.
where i indicates the waveform samples that fall in the single period specified by cycle number and numPoints is given by the following equation.
numPoints = int(period/dt + .5) where dt is the time between two points and int( ) is a function that returns the integer portion of a floatingpoint number. 

error out contains error information. This output provides standard error out functionality.  
measurement info is an array of clusters containing measurement information for each input waveform.

Refer to the following VIs for examples of using the Cycle Average and RMS VI: