Given the specification limits and the process mean and sigma, creates a graph of a normal Probability Distribution Function (PDF) of the process against the specification limits and process mean and sigma. This is a good way to represent process capability. You can turn on and off drawing of the specification limits or the natural process limits, and specify the sigma multiplier to use for the natural process limits (default 3), by wiring in the display mode. If the display mode is not wired, the specification limits and natural process limits are drawn automatically.


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Inputs/Outputs

  • ci32.png # PDF points to plot (50) —

    (I32, default 50) - The number of points to make up the Normal PDF plot. You can normally leave this unwired.

  • cdbl.png PDF width (+/- sigma) —

    (DBL, default = 3.0) - The width to draw the PDF in terms of +/- sigma. If unconnected, the PDF is drawn from - 3 sigma to + 3 sigma by default.

  • cdbl.png PDF height —

    (DBL, default = 0) - The height to draw the PDF. If 0, the PDF will be drawn with a height proportional to 1/(std dev) - corresponding to an area of 1 under the PDF curve. When fitting a normal PDF to a histogram, use the PDF Height output from the Fit Normal PDF to Histogram VI.

  • cdbl.png upper spec limit —

    (DBL) - The upper specification limit of the process.

  • cdbl.png lower spec limit —

    (DBL) - The lower specification limit of the process.

  • cdbl.png process mean —

    (DBL) - the estimated process mean. See the Process Mean & Sigma VI or Sample Statistics VI.

  • cdbl.png process sigma —

    (DBL) - the estimated process sigma. See the Process Mean & Sigma VI or Sample Statistics V.

  • ccclst.png display mode (T,T,3) —

    Optional display mode specifier. Cluster of: show spec. limits (T) (Boolean) - if true, the specification limits will be drawn. show natural process limits (T) (Boolean) - if true, the natural process limits will be drawn on the plot. NPLimit sigma (3) (U32) - The sigma multiplier for the natural process limits. By default this is 3. The natural process limits drawn will then be process mean +/- NPLimit sigma*process sigma. Note that if you wire up the display mode cluster to change one of the default settings, you must specify all three elements. If unwired, the specification limits and the natural process limits will be drawn by default.

  • cbool.png show spec limits —

    (Boolean) - if true, the specification limits will be drawn.

  • cbool.png show natural process limits —

    (Boolean) - if true, the natural process limits will be drawn on the plot.

  • cdbl.png NP limit sigma —

    (U32) - The sigma multiplier for the natural process limits. By default this is 3. The natural process limits drawn will then be process mean +/- NPLimit sigma*process sigma.

  • i1dcclst.png normal PDF graph with limits —

    (X, Y Graph) - Normal probability distribution drawn with specification limits and natural process limits.