SPC Charts - X Chart Warning Limits

Use this tab to define the following parameters:

Element Name Description
Warning Limits Use this dropdown list to select the Warning limits type:
  • None. If selected, the analysis will not generate any warning limits on the X chart.
  • Use defined UWL and LWL
  • If Use defined UWL and LWL option is selected, the analysis will look for variables named *_UWL and *_LWL for each characteristic (where '*' is the name of the characteristic) and use the values in the respective variables as the Upper warning limit and Lower warning limit values.
  • Each time the value in the *_UWL or *_LWL variable changes moving downward in the column, the system will create a new set on the X chart.
  • If a value in the *_UWL or *_LWL variable is blank, the system will use the previous valid value found in the respective column.
    • If no valid values are found in the *_UWL variable, the Calculated UWL will be used as the Variance chart UWL value if the Calculate if defined limits are blank checkbox. If this option is not selected,  the chart will not have a UWL.
    • If no valid values are found in the *_LWL variable, the Calculated LWL will be used as the Variance chart LWL value if the Calculate if defined limits are blank checkbox is selected. If it is not selected, the chart will not have a LWL.
  • Calculate UWL and LWL
  • Calculate UWL . If this option is selected, the UWL value will be computed for the X chart and there will be no LWL.
  • Calculate LWL.  If this option is selected, the LWL value will be computed for the X chart and there will be no UWL.
Check Warning Limits Select this checkbox to raise an alarm when a warning limit violation is found.
Calculate if defined limits are blank When this checkbox is selected, the warning limit will be calculated if the Use defined UWL and LWL option in the Warning Limits dropdown list, above, is checked and the variable with the defined UWL or LWL has blank or invalid values.
Process Sigma Multiplier Use this miniscroll to select a user defined process sigma multiplier for calculating the warning limits on the X chart.
Warning Limit label type Use this dropdown list to choose the Warning limit label type:
  • Text only
  • Text and number
  • Number only
  • None
Upper Warning Limit label name In this text box, enter the label for the Upper Warning limit when the Text only or the Text and number option is selected.
Lower Warning Limit label name In this text box, enter the label for the Lower Warning limit when the Text only or the Text and number option is selected.
Warning Limit violation name In this text box, enter the Warning Limit Violation name for the generated alarms spreadsheet and on the X chart legend.