Computes points and limits for X-bar and Range control Charts - control charts for process mean and range. NOTE: Sample size (number of columns in the samples X array) may not exceed 25. A range of indices for samples to be used and specific indices to ignore in the control calculation can also be specified. The actual number of samples used to calculate the control limits is supplied. FORMULAS: UCLx = x-bar-bar + stderr mult x R-bar/(d2 x sqrt(n)) CLx = x-bar-bar LCLx = x-bar-bar - stderr mult x R-bar/(d2 x sqrt(n)) standard error = R-bar/(d2 x sqrt(n)) UCLr = R-bar + stderr mult x d3 x R-bar/d2 CLr = R-bar LCLr = R-bar - stderr mult x d3 x R-bar/d2 standard error = d3 x R-bar/d2 If std error multipler = 3.0, the formulas for calculating the control limits from the data are: UCLx = x-bar-bar + A2*R-bar LCLx = x-bar-bar - A2*R-bar UCLr = D4*R-bar LCLr = D3*R-bar If std error multipler = 3.0, the formulas for calculating the control limits from given standard values: std sigma = std R0/d2 UCLx = std mean + A*std sigma LCLx = std mean - A*std sigma UCLr = D2*std sigma LCLr = D1*std sigma The constants d2, d3, A, A2, D1, D2, D3, and D4 are published in the table of factors and formulas for control charts for variables in ANSI/ASQC Standard A1-1987


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Inputs/Outputs

  • cnclst.png chart limit src —

    chart limit src specifies whether or not to use standard values for the chart limit calculations. If unwired, this cluster defaults to the common case where the chart limits are calculated from the data in the input sample 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 X-bar control chart, X-bar-bar, is set to std mean, and the center line for the s control chart, s-bar, is set to std s0, or std sigma*c4.

  • cenum.png source —

    chart limit src specifies whether or not to use standard values for the chart limit calculations. If unwired, this cluster defaults to the common case where the chart limits are calculated from the data in the input sample 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 X-bar control chart, X-bar-bar, is set to std mean, and the center line for the s control chart, s-bar, is set to std s0, or std sigma*c4.

  • cdbl.png std mean —

    chart limit src specifies whether or not to use standard values for the chart limit calculations. If unwired, this cluster defaults to the common case where the chart limits are calculated from the data in the input sample 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 X-bar control chart, X-bar-bar, is set to std mean, and the center line for the s control chart, s-bar, is set to std s0, or std sigma*c4.

  • cdbl.png std R0/sigma —

    chart limit src specifies whether or not to use standard values for the chart limit calculations. If unwired, this cluster defaults to the common case where the chart limits are calculated from the data in the input sample 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 X-bar control chart, X-bar-bar, is set to std mean, and the center line for the s control chart, s-bar, is set to std s0, or std sigma*c4.

  • c2ddbl.png samples X —

  • cnclst.png index spec —

    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.

  • ci32.png start index —

    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.

  • ci32.png end index —

    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.

  • c1di32.png indices to ignore —

    indices to ignore is the indices of samples to exclude from the control limit calculation. Excluding samples is useful for eliminating out of control points from the control limit calculation. By default, this is an empty array.

  • cdbl.png 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.

  • idbl.png X-bar-bar —

    (DBL) - this is an estimate of the process mean based on the grand average of the samples included in the control limit calculation.

  • i1ddbl.png X-bar —

  • inclst.png X-bar chart limits —

  • idbl.png UCLx —

  • idbl.png CLx —

  • idbl.png LCLx —

  • idbl.png standard error —

    standard error is the standard error associated with the center line.

  • i1ddbl.png Range R —

  • inclst.png R chart limits —

  • idbl.png UCLr —

  • idbl.png CLr —

  • idbl.png LCLr —

  • idbl.png standard error —

    standard error is the standard error associated with the center line.

  • idbl.png R-bar/d2 —

    (DBL) - This is an estimate of the process sigma (standard deviation) based on the average range of the samples included in the control limit calculation.

  • ii32.png # samples in calc —

    (I32) The number of samples used in the control limits calculation.