Since you can define more than one action rule for a collection element or collection plan element, you must assign each rule a sequence number. Assigning a number to an action rule establishes the order in which it is evaluated when the action is invoked. If the action rules are mutually exclusive, you must assign each a unique sequence number. If the action rules are non-mutually exclusive, you can assign more than one action rule to a sequence. During quality data collection, the rules are evaluated as follows:
The first rule in the sequence is evaluated.
If the rule is true, then its related action is invoked. Evaluation stops.
If the rule is not true, the next rule in the sequence is evaluated, and so on, until an action rule is evaluated as true.
When a true condition is found, the action associated with the action rule is then invoked. Evaluation stops.
When action rules are mutually exclusive, there is only one action rule for each sequence number. For example, consider the action rules associated with a collection element called "Oven Temperature":
MUTUALLY EXCLUSIVE ACTION RULES Oven Temperature = 191 degrees F. Upper to Lower specification limits = 190 to 210 degrees F. User-defined specification limits = 195 to 205 degrees F.
| Sequence | Action Rule | Action Rule Exclusivity |
|---|---|---|
| 10 | IF temp is outside the upper and lower specification limits, THEN place the job on hold | (OR) |
| 20 | IF temp is outside the user-defined specification limits, THEN display a message to operator | (OR) |
| 30 | IF temp is less than 193 degrees F., THEN send an electronic mail notification to Maintenance | - |
In this example, if an Oven Temperature value of 185 degrees F. is collected, the action rule at Sequence 10 is true and the job is placed on hold. The action rule at Sequence 20 is not evaluated even though the 185 value is outside the range specified.
If an Oven Temperature value of 192 degrees F. is collected, the action rule at Sequence 20 is the first rule to be evaluated and found to be true, thus a warning message to the operator is displayed.
When action rules are not mutually exclusive, you can define multiple action rules for each sequence number, and all action rules associated with the same sequence number are evaluated. Even if the first action rule in the sequence is evaluated as true, subsequent action rules within the same sequence also are evaluated. For example:
NON-MUTUALLY EXCLUSIVE ACTION RULES Oven Temperature = 191 degrees F. Upper and Lower specification limits = 190 to 210 degrees F. User-defined specification limits = 195 to 205 degrees F.
| Sequence | Action Rule | Action Rule Exclusivity |
|---|---|---|
| 10 | IF temp is outside the upper and lower specification limits, THEN place the job on hold | (OR) |
| 20 | IF temp is outside the user-defined specification limits, THEN display a message to operator | (AND) |
| 20 | IF temp is less than 193 degrees F., THEN send an electronic mail notification to Maintenance | - |
In this example, the two action rules assigned to Sequence 20 are non-mutually exclusive. If an oven temperature of 189 degrees F. is collected, the first action rule at Sequence 20 is found to be true, the job is placed on hold, and evaluation stops.
If an oven temperature of 192 degrees F. is collected, the action rule at Sequence 10 is not true, the action is not invoked, and the next action rule is evaluated. Sequence 20 has two action rules. If either one of the rules or if both rules are true, either or both of the actions are invoked. In this case, since an oven temperature of 192 degrees F. is both outside the user-defined specification limits and less than 193 degrees F., both rules are true, and as a result a message is displayed to the operator, and an electronic mail notification is sent to Maintenance.