Step 4.6. Set criteria for Attribute Control Tests

Set criteria.

Perform attribute control tests.

Set criteria

SPC plots the averages of the samples you define on n, nP, c and u chart sets. These charts will display the zones in which these averages fall. At runtime, each subgroup that does not meet one or more of the selected tests will be displayed with a special character (the default is a red asterisk).

The following zones are used in these tests:

Zone C is the area up to one standard deviation from the center line.

Zone B is the area between one and two standard deviations from the center line.

Zone A is the area between two and three standard deviations from the center line.

Performing multiple control tests:

In the Alarm tab of the Attribute Quality Characteristics Properties dialog box, you can run multiple control tests on your data by checking the appropriate boxes. At runtime, each data value will be compared with all of the selected alarm conditions and plotted on your configured SPC chart. When you position your cursor over the red asterisk (default character), a detailed tool tip will display with the date, time, point value and failed test data, i.e. the control test number(s).

 Note: When you create a control chart, you can select samples for exclusion.

The following example depicts the standard:

Perform attribute control tests

  1. Check the appropriate box in the Alarms tab for each of the tests to be performed.

  2. View test results by:

Accessing a configured SPC chart to view runtime data, or

Configuring a new SPC chart.

View information about Control Tests

Control Test 0

Specification Limit Test

Control Test 1

One Subgroup Beyond Upper or Lower Limits

Control Test 2

N Subgroups in a Row on Same Side of Center Line

Control Test 3

N Consecutive Subgroups in a Row all Increasing or Decreasing

Control Test 4

N Subgroups in a Row, Alternating Up and Down

Control Test 5

M out of N Subgroups in a Row in Zone A or Beyond (Same Side of Center)

Control Test 6

M out of N Subgroups in a Row in Zone B or Beyond (Same Side of Center)

Control Test 7

N Subgroups in a Row in Zone C, Above or Below Center

Control Test 8

N Subgroups in a Row Beyond Zone C, Above or Below Center

More information

SPC control test exclusion mode.

Step 4. Add and configure attribute quality characteristics.