Using Gate limits for Historical Control limits

A new GainSeeker configuration that is based on default settings will re-calculate Control Limits based on the data that is retrieved for SPC or DMS analysis, and analysis - including real-time failure checking - is based primarily on these calculated control limits.

If you prefer, you can use GainSeeker to evaluate your data relative to Historical Control Limits that you store in each SPC and DMS standard. This topic provides a reference for configuring and using GainSeeker in this manner.

 

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A. Change labels for Gate and Control

In the desired configuration:

  1. Change the Gate label to reflect that this is used for historical control limits.

  2. Change the Control label to reflect that this is used for control limits that are calculated from the current data set.

  3. Change the Chart limit labels for Lower gate, Middle gate, and Upper gate to reflect historical control limits.
    Change the Chart limit labels for Lower control, Middle control, and Upper control to reflect calculated control limits.

  4. Review your changes, then click Submit to save them.

B. Change 'Run values based on' and 'Sigma stripes based on'

In the same configuration:

  1. Change the Run values based on setting to Gate.

  2. Change the Sigma stripes based on setting to Gate.

  3. Review your changes, then click Submit to save them.

C. Change chart limits and other chart settings

Close and re-open the System Administration module. This will make your new labels display throughout the configuration.

In the same configuration:

  1. Under Chart Defaults, DMS, Control charts, change the Control chart limits.

  2. Under Chart Defaults, SPC, change the limits displayed for the following:

  3. Under Chart Defaults, SPC, check all settings for Multiple charts and Performance charts.

  4. Review your changes, then click Submit to save them.

D. Change Real-time check Defaults for New SPC standards

In the same configuration:

  1. Under Lists, Standards, and Tables, SPC, Defaults for new standards, expand the Real-time checks.

    Clear any checks that reference the calculated control limits, and select the equivalent checks against historical control limits.

  2. Review your changes, then click Submit to save them.

E. Change labels on Statistics and Real-time Failure messages

In the same configuration:

  1. Under User-defined Labels, SPC, edit the Statistics Labels.

    1. Under View statistics labels for, select the Control limits check box.

    2. All of the Statistics labels that are now listed refer to calculated control limits (not historical control limits), but their default labels are not based on the Gate, Control, and Chart Limit labels that you changed earlier.

      You can edit these labels to clarify that they are calculated control limits. You can also look up the ID code numbers for these statistics to learn more about how they are calculated.

  2. Under User-defined Labels, SPC, edit the Real-time error messages.

    These four real-time failure messages refer to calculated control limits (not historical control limits), but their default labels are not based on the Gate, Control, and Chart Limit labels that you changed earlier.

    You can edit these failure message to clarify that they refer to calculated control limits.

    The four messages are:

  3. Under User-defined Labels, DMS, edit the Statistics Labels.

    1. Under View statistics labels for, select the Control limits check box.

    2. Several Statistics labels that are now listed refer to calculated control limits (not historical control limits), but their default labels are not based on the Gate, Control, and Chart Limit labels that you changed earlier.

      You can edit these labels to clarify that they are calculated control limits. You can also look up the ID code numbers for these statistics to learn more about how they are calculated.

      The statistics whose labels you may wish to edit are:

F. (optional) Edit Short Lists, Default Statistics Reports, and Chart Skins

You can change these items now, or edit them after you start using GainSeeker with historical control limits:

  1. In the System-wide settings, you may want to edit the Short lists of most commonly-used statistics, to promote the use of historical control limits over calculated control limits.
    Please note that this change applies to all GainSeeker configurations, so use with caution.

  2. In the same configuration as above: Some SPC Default Reports and DMS Default Reports may contain statistics that reflect calculated control limits instead of historical control limits - so you may wish to edit those defaults and report formats now.

  3. In the same configuration as above: You can check SPC chart titles and DMS chart titles for statistics that reflect calculated control limits instead of historical control limits.

  4. In the same configuration as above: You can check for SPC Chart Skins and DMS Chart Skins that reflect calculated control limits instead of historical control limits. (You will probably need to test these Chart Skins in the GainSeeker Charts module, but you can change the default Chart Skins here in the configuration.)

G. Edit existing SPC and DMS standards

While a previous step set the defaults for creating new blank SPC standards, it does not affect the real-time checks for existing SPC standards.

If you already had SPC standards set up before you began changing over to historical control limits, you probably want to edit those standards to perform real-time checks against historical control limits. More importantly, you probably want to set all of the appropriate limits in these standards (if you have not done so already). The same is true if you use historical control limits for DMS standards.

When you edit an SPC standard, the settings you should review are:

When you edit a DMS standard, set the Gate limits.

If you have many standards to edit, you may find it easier to export the standards, edit the exported values in another program, and then import the new values back into GainSeeker. For details, see Importing and exporting standards.

H. Python code changes for Data Entry and Analysis

If you have Inspections, Dashboards, or other items that use GainSeeker Python scripts, check those scripts to ensure that they reference historical control limits instead of calculated control limits. This can include:

I. GainSeeker Template changes for SPC Data Entry