If daylight saving time is used at your facility, the Profile reacts accordingly. For example, when daylight saving time begins, the system clock on the supervisory controller advances from 1:59 A.M. to 3:00 A.M. If an hourly tracking period is used, the Profile starts a new tracking period at that moment, setting the Current Start Time to 3:00 A.M. and the Current End Time to 4:00 A.M. The Profile also changes the Previous Start Time to 1:00 A.M. and the Previous End Time to 3:00 A.M. The previous profile indicates that 2 hours have elapsed, but contains only 1 hour of energy data.
When daylight saving time ends, the system clock on the supervisory controller changes from 1:59 A.M. to 1:00 A.M. In this scenario, the system does not reach 2:00 A.M. until 2 hours after 1:00 A.M. The current profile contains 2 hours of profile data, even though the Current Start Time is 1:00 A.M. and the Current End Time is 2:00 A.M.
Whereas start/end date and times are not affected when the other tracking periods are used (daily, weekly, monthly, or manual), the period in which daylight saving time begins always contains 1 hour of data fewer than in a standard period. The period in which daylight saving time ends always contains 1 hour of data more than a standard period.