You may have noticed how easy it was for the Operators to open the Work Set and begin taking data. They didn't need to select which chart to use, what subgroup size was appropriate, etc.
That was decided for them when the Characteristic was added to the database.
If we right mouse click on the chart, and select Edit Characteristic (that option is also available from the Chart menu), we can see many of the different options available for each Characteristic.
The Characteristic name is entered on the General page. The Properties page (shown below) is used to specify:
· The Chart Type for Real-time Data Entry and Analysis: X-Bar / Range, X-Bar / Sigma, Individual-X / MR, Run Chart, P Chart, U Chart, Np Chart and C Chart. Subgroup sizes are from one to twenty, dependant on Chart Type. Sample sizes for P and U charts may be based on data entry or fixed at a constant level. Other charts will be discussed later for additional offline data entry or analysis.
· Control Limits: based on the plotted data, or defined by the user. When plotted data is used, the Auto Drop option removes the effect of the out of control points from the calculated limits. You may also choose to use either the Normal distribution, or the non-Normal Johnson distributions to define the Individual-X control limits, the curve displayed in the Histogram (if shown), and the Process Capability Indices calculations.
· When the Assignable Cause / Corrective Action Required option is selected, the Operator must enter the Assignable Cause and/or Corrective Action (based on whether both are Active) when subgroups violate the control limits or any of the applied Run Test rules.
· If all your data begins with the same value (for example 12.03), you can enter that as your Data Prefix. Operators will then only need to enter the value 4, and the Data Form will display and record the value as 12.034.
· Other chart options: such as warning limits and specification limits. The Rainbow chart color-codes the chart, as shown in the Length Characteristic page in the current Work Set.
