Rockwell Automation 1404-M4_M5_M6_M8 Powermonitor 3000 User Manual, Firmware rev. 3.0 or LATER - Manual (Page 177)

Publication 1404-UM001F-EN-P - November 2009 177
Advanced Features Chapter 8
Load Factor The Powermonitor 3000 M6 and M8 models provide a Load Factor Log
which calculates and stores a group of plant demand metrics that
indicates how stable (or, conversely, how dynamic) a load is over a
period of time, usually one month. Use communication to configure
load factor operation and read the results. The display module does
not support an interface to the load factor log.
Load factor is the average demand divided by the peak demand for
the month. If the load is constant, load factor is 100%. The power
monitor calculates load factor for real, reactive and apparent power
and current, and stores the last 12 results in the Load Factor Log in
non-volatile memory. You may configure the power monitor to
automatically calculate and store load factor on a particular day each
month, or you may manually generate a command by using
communication to save the load factor result and reset the calculation.
This information is useful in reducing peak demand when you look at
load factor and peak demand values. The peak demand period is
stored in the Mix/Max Log, which has a date and time stamp that
indicates when the peak occurred. Using this information, you may be
able to identify plant activities that caused the peak. You may be able
to prevent or reschedule activities, or install a demand management
system. Either option may realize significant savings in demand
charges. You can use the load factor values to estimate demand cost
savings potential. The lower the load factor, the higher the potential
for savings by managing your electric power demand.
The power monitor stores the load factor in 13 records. Record 0
stores in-progress calculations and is cleared on a power cycle.
Records 1…12 are a first-in, first-out array saved in non-volatile
memory, with the highest record number containing the most recent
record. In manual clear/reset mode, when you issue a clear/reset
command, the contents of record 0 is written to the highest-numbered
record and (if necessary) the remaining records are shifted down, with
the oldest being deleted. In auto clear/reset mode, you select a day of
the month for this process to occur automatically.
Within each record, the power monitor stores peak, average and load
factor values for real power (watts), reactive power (VARs) apparent
power (VA) and average current (amps). Peak values are the largest
such value that has occurred since the last automatic or manual
clear/reset occurrence. The in-process record (record 0) is updated at
the end of each demand interval. If no demand interval has expired
since the last unit power-up, the record will return all zeroes.