The following if from the Foglight User Help guide | Viewing, Acknowledging and Clearing Alarms:
To acknowledge one or more alarms:
1 Use the Alarm Filter to apply a filter on current or historical alarms.
2 In the Alarm(s) list, select the alarms that you want to acknowledge.
3 Click Acknowledge at the top of the table.
The current alarms are acknowledged and Yes is listed in the Ack’ed column for them. If the alarms fire again at a later time (usually because the condition has recurred), they appear in the list as unacknowledged.
4 Hover the cursor over Yes in the Ack’ed column.
A dwell appears that lists the alarm as acknowledged as well as your user name, and the time and date when you acknowledged the alarm. Foglight also stores this information in an audit report.
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To acknowledge an alarm until the alarm source returns to a normal state:
1 Use the Alarm Filter to apply a filter on current or historical alarms.
2 In the Alarm(s) list, click No in the row for the alarm.
The Alarm Details dialog box appears.
3 Click Acknowledge Until Normal.
Note This option is available for an outstanding (not-yet-cleared) alarm only.
The current alarm and all consecutive alarms fired by the same rule on the same object remain acknowledged until the first alarm fired after the alarm source returns to a normal state. Ack’ed til Normal and your user name appear in the Ack’ed Info column.
4 Close the dialog box.
In the Alarm(s) list, Foglight displays Yes in the Ack’ed column for the alarm.