6.2.2 Alarm evaluation
This subsection gives an explanation about alarm evaluation. The following legend applies to the contents of this subsection in general.
- Legend:
-
--: Not issued.
Always: Whether Always notify is selected
All: Whether Evaluate all data is selected
Y: Used (selected)
N: Not used (not selected)
- Organization of this subsection
(1) Differences among alarm evaluations depending on combinations of alarm conditions
The way an alarm is evaluated depends on the alarm conditions and the type of record to be evaluated. The following table describes the differences among alarm evaluations for various combinations of alarm conditions.
Record type |
Alarm notification |
Notification target |
Condition |
Alarm evaluation (report) |
---|---|---|---|---|
Single-instance record |
Notify when the state changed is selected |
State changes for the alarm is selected |
Evaluate all data is not selected |
If neither of the above cases is met, and the previously reported alarm was Abnormal (red) or Warning (yellow), a Normal (green) alarm is reported. |
Evaluate all data is selected |
||||
State changes for each record instance is selected |
-- |
|||
Always notify is selected |
-- |
Evaluate all data is not selected |
If either an Abnormal or Warning condition is met, an Abnormal or Warning alarm is reported, regardless of any previously reported alarm. |
|
-- |
Evaluate all data is selected |
|||
Multi-instance record |
Notify when the state changed is selected |
State changes for the alarm is selected |
Evaluate all data is not selected |
Note: As soon as any instance is found that meets a condition, alarm evaluation ends. Therefore, not all of the collected instances are always evaluated. |
Evaluate all data is selected |
Note: Because all of the instances are evaluated, more than one alarm can be reported in one interval. |
|||
State changes for each record instance is selected |
-- |
Note: Because all of the instances are evaluated, more than one alarm can be reported in one interval. |
||
Always notify is selected |
-- |
Evaluate all data is not selected |
Note: As soon as any instance is found that meets a condition, alarm evaluation ends. Therefore, not all of the collected instances are always evaluated. |
|
-- |
Evaluate all data is selected |
For each instance that meets either an Abnormal or Warning condition, an Abnormal or Warning alarm is reported. Note: Because all of the instances are evaluated, more than one alarm might be reported in one interval. |
Record type |
Alarm notification |
Notification target |
Condition |
Alarm evaluation (report) |
---|---|---|---|---|
Multi-instance record |
Notify when the state changed is selected |
State changes for the alarm is selected |
Evaluate all data is not selected |
All of the collected instances are checked for the values specified in the New Alarm > Alarm Conditions window or the Edit > Alarm Conditions window, and if no such values are found (none of the conditions are met), an Abnormal (red) alarm is reported. Note: An alarm notifying of no operation is reported only once. If no instance is collected, the alarm is not evaluated. |
Evaluate all data is selected |
||||
State changes for each record instance is selected |
-- |
--# |
||
Always notify is selected |
-- |
Evaluate all data is not selected |
All of the collected instances are checked for the values specified in the New Alarm > Alarm Conditions window or the Edit > Alarm Conditions window, and if no such values are found (none of the conditions are met), an Abnormal (red) alarm is reported. Note: An alarm is reported every time. If no instance is collected, the alarm is not evaluated. |
|
-- |
Evaluate all data is selected |
The alarm evaluation method is explained for various alarm conditions below.
- When you select Monitor whether the value exists:
-
All fields in records of PD and PI record types that are specified in alarm conditions are evaluated to check for the specified value. If the value is not found, the alarm is reported once per interval.
- When you set alarm conditions:
-
When you set alarm conditions, multiple records are collected in one interval for the record of PD and PI record types to be evaluated in this alarm. If you do not select Evaluate all data, as soon as the first instance is found that meets the conditional expression, an alarm is reported and evaluation ends. Therefore, to evaluate all the performance data in an alarm, select Evaluate all data or State changes for each record instance.
(2) Differences among alarm evaluations depending on whether Damping is enabled
In addition to the differences among alarm evaluations for various alarm conditions, if you set Damping, other differences are added to the alarm evaluation. The following table describes the differences among alarm evaluations for various alarm conditions with damping.
Damping |
Always |
All |
Alarm evaluation (notification) |
---|---|---|---|
Y |
N |
N |
Note: Because the status of the alarm is determined by evaluating the damping condition, the status of the alarm might differ from the threshold of the reported instance. |
Y |
N |
Y |
Note: Because the status of the alarm is determined by evaluating the damping condition, the status of the alarm might differ from the threshold of the reported instance. |
Y |
Y |
N |
The instance that indicates the highest severity at the time of reporting the alarm is reported. |
Y |
Y |
Y |
All data that meets the warning or abnormal condition at the time of reporting the alarm is reported. |
The following table describes the differences when alarms are reported depending on the value set for Damping.
Damping |
|
---|---|
n/m |
The alarm is reported when the threshold is exceeded n times during m evaluations of the alarm. Subsequently, the alarm is reported every time the threshold is exceeded n times during m evaluations of the alarm. |
n/n# |
If the threshold continues to be exceeded, the alarm is reported every n evaluations. This is useful when you do not want alarms that have exceeded a threshold to be continuously reported. |
(3) Evaluating alarms with a monitoring time range and damping conditions specified (when "State changes for each record instance" is not selected)
If you specify a monitoring time range, a normal alarm is issued at the specified end time. However, in calculating alarm damping, the system includes previous monitoring time ranges. An example of evaluating an alarm with a monitoring time range specified is given below.
- Alarm conditions
-
-
Monitoring time range: 9:00 to 21:00
-
Damping: Threshold exceeded twice in three evaluations
-
Always notify: Not selected
-
Evaluate all data: Not selected
-
The alarm enters abnormal or warning status when the threshold is exceeded twice inside the monitoring time range for that day. When the monitoring time range is over, the alarm reverts to normal status. The following day, the status of the monitoring agent at the end of the previous day's monitoring time range (in this case abnormal or warning) is inherited at the start of the monitoring time range on the following day. Therefore, when the threshold is first exceeded in the monitoring time range of the following day, the condition of exceeding the threshold twice in three evaluations is met, and an abnormal or warning alarm is issued.
In this scenario, alarms are issued as follows:
Day |
Time |
Monitoring agent status |
Issued alarm |
|
---|---|---|---|---|
First |
20:58 |
Inside monitoring time range |
Normal |
-- |
20:59 |
Abnormal |
-- |
||
21:00 |
Abnormal |
Abnormal alarm#1 |
||
21:01 |
Outside monitoring time range |
Not evaluated |
Normal alarm#2 |
|
21:02 |
Not evaluated |
-- |
||
: |
||||
Second |
8:59 |
Outside monitoring time range |
Not evaluated |
-- |
9:00 |
Inside monitoring time range |
Abnormal |
Abnormal alarm#3 |
(4) Evaluating alarms with a monitoring time range and damping conditions specified (when "State changes for each record instance" is selected)
If you specify a monitoring time range, a normal alarm is issued at the specified end time.
When State changes for each record instance is selected and the time is outside the monitoring time range, the damping value is cleared and an alarm event (Alarm Expired) is reported once. When the time is in the monitoring time range, a new evaluation starts as is the case with alarm binding.
An example of evaluating an alarm with a monitoring time range specified is given below.
- Alarm conditions
-
-
Monitoring time range: 9:00 to 21:00
-
Damping: Threshold exceeded twice in three evaluations
-
State changes for each record instance: Selected
-
Evaluate all data: Not selected
-
The alarm enters abnormal or warning status when the threshold is exceeded twice inside the monitoring time range for that day. When the monitoring time range is over, the alarm reverts to normal status. The following day, the status of the monitoring agent at the end of the previous day's monitoring time range (in this case abnormal or warning) is not inherited at the start of the monitoring time range. Therefore, when the threshold is exceeded twice in the monitoring time range of the following day, the condition of exceeding the threshold twice in three evaluations is met.
In this scenario, alarms are issued as follows:
Day |
Time |
Monitoring agent status |
Issued alarm |
|
---|---|---|---|---|
First |
20:58 |
Inside monitoring time range |
Normal |
-- |
20:59 |
Abnormal |
-- |
||
21:00 |
Abnormal |
Abnormal alarm#1 |
||
21:01 |
Outside monitoring time range |
Not evaluated |
Normal alarm#2 |
|
21:02 |
Not evaluated |
-- |
||
: |
||||
Second |
8:59 |
Outside monitoring time range |
Not evaluated |
-- |
9:00 |
Inside monitoring time range |
Abnormal |
--#3 |
|
9:01 |
Abnormal |
Abnormal alarm#1 |