ISA-18.2 defines the states an alarm moves through. One of them is returned to normal, unacknowledged: the condition cleared before anybody acknowledged it. The alarm grid keeps these alarms on the summary until they are acknowledged, so an intermittent fault stays visible.
Select a row, then acknowledge or shelve it.
Filters change the view but not the counts. An operator who has filtered the list to one area still needs to know how many unacknowledged alarms the plant has, so counts() always describes the whole alarm list.
Operator and engineering overrides take precedence over the process condition. Out of service is a maintenance decision and takes precedence over suppression, which is a design decision. A shelved alarm returns when the shelf expires.
| State | Means | Still needs an operator? |
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