User`s manual

The formula for calculating UCLx is: mean + (sigma x
sigma units).
The formula for calculating LCLx is:
mean - (sigma x
sigma units).
Chart Attributes Method: Chart A and Chart B
Note: These fields apply only when you have selected a p
chart option for chart A and/or chart B.
Use these fields to select the “attribute” that determines
whether an inspected item is defective. You can select the
same “attribute method” or different methods for each p
chart, according to the requirements of your application.
Here. are some requirements to keep in mind when selecting
the attribute method:
1. When you select “Result out of spec,” you must enter
both specification limits, since the CSS calculates the
-
percentage of defective items @) as the number of
items whose inspection result is outside either
specification limit divided by the number of items in
the sample.
2. When you select “Result above USL” you must enter
the upper specification limits; when you select “Result
below LSL,” you must enter the lower specification
limit.
3. When you select either “Discrete output closed” or
“Discrete output open,” you do not need to enter
specification limits.
When you highlight either chart attributes field, the p Chart
Attributes Method Menu appears on the display, as shown
in Figure 8.15 on page 8-37.
8-36