Outside Zone C Limit Alarm 
Alarm rule 8 is triggered when multiple points (in a series) are outside upper or lower Zone C.
For alarm rule 8, the limit and length values are used for both the upper and lower charts. The data points on the chart are checked for the specified number of points outside zone C. For alarm rule 8, an alarm is triggered when there are <Limit> number of data points in the <Length> that are outside upper or lower Zone C. You can also use other alarms 42 or 43.
Features
General guidelines to detect instability outside Zone C for different chart types are as follows:
Chart Type | Maximum Points to apply Rule |
|---|---|
X-bar | 15 consecutive points outside Zone C |
Individual | |
Median | |
R-Chart when the minimum subgroup size is 4 | |
R-Chart when the minimum subgroup size less than 4 | 10 consecutive points outside Zone C |
Following are the alarm properties defined for Outside Zone C Limit Alarm:
Alarm Name | Property Name | Parameter Name | Data Type | Description |
|---|---|---|---|---|
Allow Upper Chart Outside Zone C Limit Alarm | UpperWEOutsideZoneCAlarmEnabled | Boolean | Enables outside Zone C alarm points for upper charts | |
Allow Lower Chart Outside Zone C Limit Alarm | LowerWEOutsideZoneCAlarmEnabled | Boolean | Enables outside Zone C alarm points for lower charts | |
Alarm 8 | Limit of Outside Zone C Limit Alarm | WEOutsideZoneCAlarmLimit | Integer | Sets the limit and length to check for alarms that fall outside Zone C |
Length of Outside Zone C Limit Alarm | WEOutsideZoneCAlarmLength | Integer | ||
Alarm 42 | Limit of Upper Chart Outside Zone C Limit Alarm | WEUpperChartOutsideZoneCAlarmLimit | Integer | Defines the limit and length values to check for points outside Zone C of the upper chart |
Length of Upper Chart Outside Zone C Limit Alarm | WEUpperChartOutsideZoneCAlarmLength | Integer | ||
Alarm 43 | Limit of Lower Chart Outside Zone C Limit Alarm | WELowerChartOutsideZoneCAlarmLimit | Integer | Defines the limit and length values to check for points outside Zone C of the lower chart |
Length of Lower Chart Outside Zone C Limit Alarm | WELowerChartOutsideZoneCAlarmLength | Integer |
Example
If you define alarm rule 42 with limit and length as 15 each, the alarm rule 42 is violated if only 15 points in a string of 15 adjacent points in the upper chart are outside upper or lower Zone C.
Graphical representation of Outside Zone C Limit Alarm:
