ACR Electronics PowerWatch Reference Manual page 55

PowerWatch Operating Overview
48
Event # Column
The Events column displays the number sequence of each event, with the
most recent events displayed first. By using the scroll bar on the right of the
window, all the events that the VDR has recorded can be viewed. The number
0 is given to an Open Event.
Start Time Column
The Start Time column displays the time that an event started. The resolution
of the time stamp in a VDR is eight seconds. Therefore, if an impulse occurred
once every second starting at 12:00:00, the first eight impulses would all be
reported to have the same time of 12:00:00. The next eight impulses would be
reported as having the same time of 12:00:08. Also, if identical information
was downloaded twice from a VDR, the two site reports could show a time
difference of eight seconds.
Event Column
The Event column displays the types of events that occurred during the
reporting period.
Impulse Events An Impulse Event is a transient voltage surge. The event
column will display the number of impulses that the VDR was able to count.
For instance, in the Event tab displayed above, event #8 is one impulse; event
#18 is made up of nine impulses.
Surge and Sag Events Surge and sag events are increases and decreases
in line voltage that are outside the thresholds for at least one full cycle. Surges
2007 ACR Systems Inc.