Schneider Electric PM870 Manual De Usuario
© 2011 Schneider Electric. All Rights Reserved.
PowerLogic
TM
Series 800 Power Meter
63230-500-225A2
Chapter 4—Metering Capabilities
3/2011
32
Synchronized Demand
The demand calculations can be synchronized by accepting an external pulse input, a
command sent over communications, or by synchronizing to the internal real-time clock.
command sent over communications, or by synchronizing to the internal real-time clock.
•
Input Synchronized Demand. You can set up the power meter to accept an input such
as a demand synch pulse from an external source. The power meter then uses the
same time interval as the other meter for each demand calculation. You can use the
standard digital input installed on the meter to receive the synch pulse. When setting up
this type of demand, you select whether it will be input-synchronized block or input-
synchronized rolling block demand. The rolling block demand requires that you choose
a sub-interval.
as a demand synch pulse from an external source. The power meter then uses the
same time interval as the other meter for each demand calculation. You can use the
standard digital input installed on the meter to receive the synch pulse. When setting up
this type of demand, you select whether it will be input-synchronized block or input-
synchronized rolling block demand. The rolling block demand requires that you choose
a sub-interval.
•
Command Synchronized Demand. Using command synchronized demand, you can
synchronize the demand intervals of multiple meters on a communications network. For
example, if a PLC input is monitoring a pulse at the end of a demand interval on a utility
revenue meter, you could program the PLC to issue a command to multiple meters
whenever the utility meter starts a new demand interval. Each time the command is
issued, the demand readings of each meter are calculated for the same interval. When
setting up this type of demand, you select whether it will be command-synchronized
block or command-synchronized rolling block demand. The rolling block demand
requires that you choose a sub-interval. See Appendix C—Using the Command
Interface on page 83 for more information.
synchronize the demand intervals of multiple meters on a communications network. For
example, if a PLC input is monitoring a pulse at the end of a demand interval on a utility
revenue meter, you could program the PLC to issue a command to multiple meters
whenever the utility meter starts a new demand interval. Each time the command is
issued, the demand readings of each meter are calculated for the same interval. When
setting up this type of demand, you select whether it will be command-synchronized
block or command-synchronized rolling block demand. The rolling block demand
requires that you choose a sub-interval. See Appendix C—Using the Command
Interface on page 83 for more information.
•
Clock Synchronized Demand (Requires PM810LOG). You can synchronize the
demand interval to the internal real-time clock in the power meter. This enables you to
synchronize the demand to a particular time, typically on the hour. The default time is
12:00 am. If you select another time of day when the demand intervals are to be
synchronized, the time must be in minutes from midnight. For example, to synchronize
at 8:00 am, select 480 minutes. When setting up this type of demand, you select
whether it will be clock-synchronized block or clock-synchronized rolling block demand.
The rolling block demand requires that you choose a sub-interval.
demand interval to the internal real-time clock in the power meter. This enables you to
synchronize the demand to a particular time, typically on the hour. The default time is
12:00 am. If you select another time of day when the demand intervals are to be
synchronized, the time must be in minutes from midnight. For example, to synchronize
at 8:00 am, select 480 minutes. When setting up this type of demand, you select
whether it will be clock-synchronized block or clock-synchronized rolling block demand.
The rolling block demand requires that you choose a sub-interval.
Thermal Demand
The thermal demand method calculates the demand based on a thermal response, which
mimics thermal demand meters. The demand calculation updates at the end of each
interval. You select the demand interval from 1 to 60 minutes (in 1-minute increments). In
Figure 4–5 the interval is set to 15 minutes for illustration purposes.
mimics thermal demand meters. The demand calculation updates at the end of each
interval. You select the demand interval from 1 to 60 minutes (in 1-minute increments). In
Figure 4–5 the interval is set to 15 minutes for illustration purposes.
Demand Current
The power meter calculates demand current using the thermal demand method. The
default interval is 15 minutes, but you can set the demand current interval between 1 and
60 minutes in 1-minute increments.
default interval is 15 minutes, but you can set the demand current interval between 1 and
60 minutes in 1-minute increments.
Figure 4–5: Thermal Demand Example
15-minute
interval
next
15-minute
interval
Time
(minutes)
Calculation updates at the end of each interval
The interval is a window of time that moves across the timeline.
Last completed
demand interval
demand interval
99%
90%
% of L
oad
0%