Resampling for Power Measurement VI

Owning Palette: Harmonics VIs

Requires: Electrical Power Toolkit

Resamples even-time-spaced voltage and current signals into even-angle-spaced signals for harmonic analysis, according to the trigger times that you specify.

If you set the minimum fundamental frequency too low or set the transition band too narrow in the Reference Signal Processing (Zero Crossing) VI, this VI requires a large amount of memory to process the voltage and current signals.

Example

	reset? specifies whether to reset the resampling process. The default is FALSE. When you call this VI for the first time, the resampling process resets automatically.
	data in specifies the voltage or current signal. t0 specifies the start time of the waveform. dt specifies the time interval, in seconds, between data points in the waveform. Y specifies the data values of the waveform.
	trigger information specifies the time and number of the triggers that this VI uses to resample the voltage and current signals. trigger times specifies the time, in seconds, when triggers occur. trigger times must be synchronous with data in. You can use zero crossing times that you calculate with the Reference Signal Processing (Zero Crossing) VI as trigger times for this VI. You also can use the pulse times that a tachometer generates as trigger times for this VI. triggers per cycle specifies the number of triggers in one cycle of the voltage and current signals. The default is 2.
	samples per cycle specifies the number of samples per cycle for the resampling process. The default is 192. You must set samples per cycle to be greater than or equal to (2 * maximum harmonic order) + 1. If you set samples per cycle too low, the measurement result might not be accurate enough. A greater samples per cycle value requires more real-time computation resources to process the resampled signal.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	resampled data returns the resampled signal for harmonic analysis. resampled data is synchronous with the fundamental frequency with the number of samples per cycle that you specify in samples per cycle. times returns the time instants of the resampled signals in seconds. resampled signal returns the resampled voltage and current signals.
	error out contains error information. This output provides standard error out functionality.

Example

Refer to the Advanced Power Measurement - Harmonics (DAQmx) VI in the labview\examples\Electrical Power\Power Measurement directory for an example of using the Resampling for Power Measurement VI.