RMS (Half Cycle) VI

Owning Palette: U, I & Freq VIs

Requires: Electrical Power Toolkit

Calculates the RMS voltage or RMS current for a half/single-cycle block, by using the zero crossings. You can use the Zero Crossing VI to calculate zero crossing. This VI refreshes the RMS values every half-cycle. You use the half/single-cycle RMS values only for detection of voltage dips, swells, and interruption events, detection of rapid voltage changes, and measurement of flickers.

This VI supports measuring single-line and multiple-line systems.

Details  Examples

	reset? specifies whether to reset the calculation process. The default is FALSE. When you run this VI for the first time, the calculation process resets automatically.
	waveforms specifies voltage or current waveforms. Each array element represents one phase and contains samples representing 10-cycle time interval for a 50 Hz power system or 12-cycle time interval for a 60 Hz power system. Voltage waveforms are in volts and current waveforms are in amperes. 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.
	zero crossing specifies the zero crossing index.
	system info in specifies the basic configuration of the electrical power system. Use the Initialize System VI to generate the basic configuration information.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	one-cycle RMS returns RMS values measured over one cycle. The measurement starts at fundamental zero crossing and refreshes each half-cycle. Each element of this array corresponds to one element of input waveforms array. timestamps returns timestamps of the end of each signal half-cycle. RMS values returns the RMS values measured over one cycle.
	half-cycle RMS returns RMS values measured over half cycle. The measurement starts at fundamental zero crossing and refreshes each half-cycle. Each element of this array corresponds to one element of input waveforms array. timestamps returns timestamps of the end of each signal half-cycle. RMS values returns the RMS values measured over half cycle.
	system info out returns information about the basic configuration of the electrical power system.
	error out contains error information. This output provides standard error out functionality.

RMS (Half Cycle) Details

Related Information
Line and Bus Configurations

Examples

Refer to the following VIs for examples of using the RMS (Half Cycle) VI:

• Events Detection (DAQmx) VI: labview\examples\Electrical Power\Power Quality\Applications (DAQmx)
• Events Detection VI: labview\examples\Electrical Power\Power Quality\Applications (cRIO) (Delta-Sigma)
• Events Detection VI: labview\examples\Electrical Power\Power Quality\Applications (cRIO) (SAR)