Schneider Electric 4000

63230-300-212 Chapter4—Metering Capa bilities

April 2001 DemandReadings

The demand calculationscan be synchronized by accepting an external

pulse input,a command sent over communications, or by synchronizingto

the internal real-timeclock.

•Input Synchronized Demand.You can set up the circuit monitor to

accept an input suchas a demandsynch pulse from an external source.

Thecircuit monitor then uses the same time interval as the othermeter for

each demand calculation.You can use any digital inputinstalled on the

meter to receivethe synch pulse. When setting up this type of demand,

you select whetherit will be input-synchronized block or input-

synchronizedrolling block demand. The rolling block demand requires

that you choose a subinterval.

•Command SynchronizedDemand. Using command synchronized

demand,you can synchronize the demand intervalsof multiple meters on

a communicationsnetwork. For example, if a PLC input is monitoringa

pulseat the end of a demand interval on a utility revenue meter,you could

program the PLC to issuea command to multiple meters whenever the

utility meterstar ts a newdemand interval. Each time the command is

issued, the demand readingsof each meter are calculated for the same

interval.When setting up this type of demand, you selectwhether it will be

command-synchronizedblock or command-synchronized rollingblock

demand.The rolling block demand requires thatyou choose a subinterval.

See Appendix B—Usingthe Command Interface on page 181 for

more information.

•ClockSynchronized Demand. Youcan synchronize the demandinterval

to the internal real-timeclock in the circuit monitor. This enables you to

synchronizethe demand to a particular time, typically on the hour. The

defaulttime is 12:00 am. If you select another time of day when the

demand intervalsare to be synchronized, the time must be in minutes

from midnight.For example, to synchronize at 8:00 am, select480

minutes.W hen settingup this type of demand, you select whether it will

be clock-synchronizedblock or clock-synchronizedrolling block demand.

The rolling blockdemand requires that you choose a subinterval.

The circuitm onitorcalculates demand current using the thermal demand

method. The defaultinterval is 15 minutes, but you can set the demand

current intervalbetween 1 and 60 minutes in 1-minute increments.

The circuitmonitor calculates demand voltage. The default voltagedemand

modeis thermal demand with a 15-minute demand interval. Youcan also set

the demandvoltage to any of the blockinterval demand modes described in

“Block IntervalDemand”on page 57.

SynchronizedDemand

Demand Current

Demand Voltage