Filter
Top Products
© 2011 Schneider Electric. All Rights Reserved.
63230-500-225A2 PowerLogic
TM
Series 800 Power Meter
3/2011 Chapter 4—Metering Capabilities
31
Block Interval Demand
In the block interval demand method, you select a “block” of time that the power meter uses
for the demand calculation. You choose how the power meter handles that block of time
(interval). Three different modes are possible:
• Sliding Block. In the sliding block interval, you select an interval from 1 to 60 minutes
(in 1-minute increments). If the interval is between 1 and 15 minutes, the demand
calculation updates every 15 seconds. If the interval is between 16 and 60 minutes, the
demand calculation updates every 60 seconds. The power meter displays the demand
value for the last completed interval.
• Fixed Block. In the fixed block interval, you select an interval from 1 to 60 minutes (in
1-minute increments). The power meter calculates and updates the demand at the end
of each interval.
• Rolling Block. In the rolling block interval, you select an interval and a sub-interval.
The sub-interval must divide evenly into the interval. For example, you might set three
5-minute sub-intervals for a 15-minute interval. Demand is updated at each sub-
interval. The power meter displays the demand value for the last completed interval.
Figure 4–4 below illustrates the three ways to calculate demand power using the block
method. For illustration purposes, the interval is set to 15 minutes.
Figure 4–4: Block Interval Demand Examples
15 30 45
15 30 45
60 . . .
15
30 45
20 35 4025
PLSD110131
Demand value is the
average for the last
completed interval
Demand value is
the average for
the last
completed
interval
Demand value is
the average for
the last
completed
interval
Time
(sec)
Time
(min)
Time
(min)
Calculation updates
every 15 or 60
seconds
Calculation updates at
the end of the interval
Calculation updates at the end of
the sub-interval (5 minutes)
Sliding Block
Fixed Block
Rolling Block
15-minute interval
15-minute interval
15-minute interval 15-min
15-minute interval