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Chapter 5—Input/Output Capabilities 63230-300-212
Demand Synch Pulse Input April 2001
© 2001 Schneider Electric All Rights Reserved
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You can configure the circuit monitor to accept a demand synch pulse from
an external source such as another demand meter. By accepting demand
synch pulses through a digital input, the circuit monitor can make its demand
interval “window” match the other meter’s demand interval “window.” The
circuit monitor does this by “watching” the digital input for a pulse from the
other demand meter. When it sees a pulse, it starts a new demand interval
and calculates the demand for the preceding interval. The circuit monitor
then uses the same time interval as the other meter for each demand
calculation. Figure 5–1 illustrates this point. See “Synchronized Demand” on
page 59 in Chapter 4—Metering Capabilities for more about demand
calculations.
When in demand synch pulse operating mode, the circuit monitor will not
start or stop a demand interval without a pulse. The maximum allowable time
between pulses is 60 minutes. If 66 minutes (110% of the demand interval)
pass before a synch pulse is received, the circuit monitor throws out the
demand calculations and begins a new calculation when the next pulse is
received. Once in synch with the billing meter, the circuit monitor can be used
to verify peak demand charges.
Important facts about the circuit monitor’s demand synch feature are listed
below:
• Any installed digital input can be set to accept a demand synch pulse.
• Each system can choose whether to use an external synch pulse, but only
one demand synch pulse can be brought into the meter for each demand
system. One input can be used to synchronize any combination of the
demand systems.
• The demand synch feature can be set up from
SMS. See the SMS online
help for instructions on device set up of the circuit monitor.
Figure 5–1: Demand synch pulse timing
DEMAND SYNCH PULSE INPUT
Billing Meter
Demand Timing
Circuit Monitor
Demand Timing
Normal Demand Mode
Billing Meter
Demand Timing
Circuit Monitor
Demand Timing
(Slaved to Master)
External Synch Pulse Demand Timing
Utility Meter
Synch Pulse