Eaton Power Xpert PXM 4000, Руководство пользователя и инструкция по установке

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6 Functions on the Web Server Pages
DEMAND
Demand is the power consumption at the receiving terminal averaged over a specific interval of
time or in response to a signal at a designated discrete input. The Power Xpert Meter is capable
of measuring demand by two internally triggered methods; Fixed or Sliding in intervals of 1 to 60
minutes. These measurements are configured to calculate the Total Current, kW Forward/Reverse,
Net and Sum; kVar Lead/Lag, Net and Sum and kVA.
FIXED AND SLIDING DEMAND
Fixed demand (Total Current), which is an average system current over time can be set to average
current over a range of 1 to 60 minutes. This is known as a fixed window. For example, setting the
current demand window to 15 sets the meter to determine the average current over the past 15
minutes and update the value every 15 minutes.
Power demand can be fixed, as described above, or sliding. For example, a 15 minute average can
be obtained that is updated every 3 minutes. To accomplish this, the subinterval is set to 3 minutes
and the number of intervals is set to 5 (i.e. 3 minutes times 5 intervals equals 15 minutes).
NOTE:
The demand interval is the number of minutes in the average calculation. The subinterval is
the number of minutes between updates.
Separate demand values are computed on a monthly basis. At the end of every calendar month,
peak demand values with date and time stamps are saved as last months values. Peak demand is
reset and new peak demand calculations begin for next month.
In the absence of an External Synchronization, the Power Xpert Meter starts demand windows
according to the real-time clock at the top of the hour and top of the minute. In the typical case of a
15-minute window, the intervals would start at the top of the hour, at 15 minutes past the hour, half-
past the hour, and 45 minutes past the hour.
Demand reset can be executed using any available user interface or it can be scheduled in the
calendar. When the demand reset occurs a snapshot of all peak demand values and energy values
are saved as last demand reset values and demand reset count, with date and time.
Snapshots of peak demand values with date and time stamps and energy values are saved in a file
each time the demand reset is executed. This self-read process can also be initiated by using the
calendar schedule. The latest five snapshots are available in a file.