Cp,cpk

[Ravi1995]

Hi 

    I would like to calculate cp,cpk values with out using spc toolkit.I have generated cp,cpk values but it is not matching with minitab cp,cpk values.In minitab there are two types of capabilities.In my VI genertaed values are matching with overall capability.I am unable to find how to calculate cp,cpk values with in limit.Can any one help me in calculating cp,cpk values.Here You can find link for https://www.isixsigma.com/tools-templates/capability-indices-process-capability/cp-cpk-pp-and-ppk-kn...

with in limit.

Thanks

Ravi 

[cbutcher]

If you upload a file with a comma in the filename, it becomes undownloadable from these forums (multiple headers error)

The link you specified seems to show formulas for each of the coefficients you want to calculate. I expect you could calculate these fairly simply using LabVIEW, but without seeing your code I can't guess how close or far away you might be, or what you could improve!

[RavensFan]

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@cbutcher wrote:

If you upload a file with a comma in the filename, it becomes undownloadable from these forums (multiple headers error)

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That's odd because when I clicked on the link, it opened up just fine.

[altenbach]

As a first step, you need to learn the LabVIEW basics. Your Vi is full of race conditions fixed by crazy extra code.

There is a glaring race conditions because the "mean local might get read before the indicator has been written. You "fix" that by the outer FOR loop causing the same calculation to be done twice and in the second round the mean has the new value. Crazy!

• If you would eliminate the local and use a proper wire, the outer FOR loop can be deleted.
• Your inner FOR loop can be removed without any change in outcome!
• There is a primitive to calculate the mean of an array.
• You are calculating the variance, not the covariance
• Why do you calculate 3xSD twice. Once is sufficient!
• Please don't link to questionable sites peppered with ads.

Here is a :"literal" cleanup of your code (i.e. no change is result!  which is apparently wrong but can still see to properly write a LabVIEW code.)

Now just go back to the documentation and fix it (I won't look at pages peppered with advertisements. Maybe start reading here instead!).