Control Chart Setup

Explanation

This activity is used to setup statistical process control (SPC) for a specific data point in a specific control plan. The setup is used both when creating control charts manually and when they are created automatically using Real Time SPC.

 During the setup, a control chart type is chosen. There exists several control chart types.

The available control chart types that can be chosen is depending on the data type and the inspection type the specific data point has.

Control charts are used to analyze a process or its outputs and take appropriate actions to achieve and maintain a state of statistical control. A process is in statistical control ("in control") when all special causes of variation have been eliminated and only common causes remain, i.e., observed variation can be attributed to a constant system of chance causes.

Several statistical tests (alarm rules) can be activated to determine whether the control chart is "in control" or "out of control".

Out of Specification: An alarm rule violation will be triggered when a point in the control chart is above Inner Max or Outer Max or below Inner Min or Outer Min.

If an alarm rule violation occurs for an activated alarm rule, information about the alarm rule violation will be displayed in the control chart.

It is also possible to decide if any specification limits should be displayed in the chart and how to calculate the control chart control limits.

To set up SPC for a data point click Setup SPC Data on the Control Plan Lines tab and enter the settings in the Variable SPC Setup dialog. To see the default settings of the SPC setup, click Default Settings. To activate the control chart setup click Save Settings.

Prerequisites

System Effects

As a result of this activity, the control chart type is determined for a specific data point in a specific control plan. Decisions are also made about how to calculate control limits, whether to include specification limits in the control chart, and whether one or many alarm rules should be activated.