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Owning Palette: Control Charts VIs

Installed With: Statistical Process Control Toolkit

Computes points and limits for a c chart, a control chart for number of non-conformities or defects. Optionally, you can choose a range of indices for samples to use and indices of samples to ignore in the control calculation. The actual number of samples the VI uses to calculate the control limits is also output. By default, control limits are calculated from the input samples. You can also calculate control limits from standard values by wiring the chart limit src input.

Details  

	chart limit src specifies whether or not to use standard values for the chart limit calculations. If unwired this defaults to the most common case where the chart limits are calculated from the data in the input array. You do not have to wire this cluster unless you want the chart limits to be calculated from standard values. When using standard values, the center line for the control chart, c-bar, is set to c0. source provides two choices for source of chart limits calculation. 0 from data—(Default) chart limits are calculated from data. 1 std c0—chart limits are calculated from standard given c0. std c0 is the standard c0 to use in calculating chart limits, in case of standard given.
	c:# defects/sample is the number of non-conformities or defects per sample inspected.
	std error multiplier (3) (DBL, default = 3.0). Ordinarily you would leave this unwired and the control chart limits are computed as +/- 3.0 standard errors.
	index spec is used to choose a range of samples in c to use for the control limit calculation. If you do not wire this cluster, all elements in c input array are included in the control limit calculation. start index is the index of the first element of c to include in the control limit calculation. Default is 0 or index of the first sample in the c array. end index is the index of the last element of c to include in the control limit calculation. Default is 0 which selects the last sample in the c array.
	indices to ignore defines the indices of c to exclude from the control limit calculation. This is useful for eliminating out of control points from the control limit calculation. By default, this is an empty array.
	# samples in calc is the number of samples used in the control limits calculation.
	c:# non-conformities/inspection unit is the number of non-conformities or defects found per sample unit, which is identical to the input array c. These are the points plotted on the c control chart.
	c chart limits contains the limits for one c chart. UCLc is the upper control limit for the c chart. If std error multiplier is 3, this will be c-bar + 3 standard errors. c-bar is the center line c-bar for the c control chart. c-bar is the estimated number of non-conformities for the process. LCLc is the lower control limit for the c chart. If std error multiplier is 3, this will be np-bar - 3 standard errors. standard error is the standard error associated with c-bar.

c Chart Details

if calculated from the input data, otherwise