A logic manager monitors changing tag values, evaluates downtime definitions, and records downtime events to the database. If the logic manager detects that a system is down or slowing production, it notifies an event manager operating on each HMI node or PC. "Many times the most painful downtimes are of a short duration, but they happen frequently," explains Kevin Tock, senior vice president and general manager of Wonderware Corp. "Operators become used to clearing a system fault quickly, and no longer consider the downtime associated with 10 or 20 twominute fixes. They also fail to notice other problems taking place upstream or downstream as a result of starting and stopping a production line. Therefore, downtime can be attributed to the wrong piece of equipment." Operators can respond to alarms and manually enter related information, such as planned downtimes, through the event manager.