Name of the operator who acknowledged this Event. This is a read-only property and its value can be:

•Elipse E3 Viewer's logged-in user, when acknowledgment is performed on E3Alarm, or "No user" if there is no logged-in user

•"System", when acknowledgment is automatic, that is, for Events that ask for acknowledgment

•A name passed by script, such as when using Alarm Server's AckAllAlarms, AckArea, or Alarm Source's Ack method