TPU2000/2000R Modbus/Modbus Plus/ Modbus TCP/IP Automation Guide
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40656 Demand kVars Phase A Unsigned 32 Bit Low Order Word LSW
40657 Demand kVars Phase B Unsigned 32 Bit High Order Word MSW
40658 Demand kVars Phase B Unsigned 32 Bit Low Order Word LSW
40659 Demand kVars Phase C Unsigned 32 Bit High Order Word MSW
40660 Demand kVars Phase C Unsigned 32 Bit Low Order Word LSW
40661 3 Phase Demand Watts Unsigned 32 Bit High Order Word MSW
40662 3 Phase Demand Watts Unsigned 32 Bit Low Order Word LSW
40663 3 Phase Demand Vars Unsigned 32 Bit High Order Word MSW
40664 3 Phase Demand Vars Unsigned 32 Bit Low Order Word LSW
Minimum and Maximum Peak Demand (60 Registers Defined)
Peak Demands are monitored and logged within the TPU2000 and TPU2000R. The demands are constantly
logged by the IED until reset by the operator. The reset bit is located in register 41410 through 41415. Please
reference Section 5 for the procedure to initiate Minimum and Maximum Peak Value reset. Each value is time-
stamped and the peak value is stored. The values are compared every 2 seconds. If the new value is greater
than the previous stored value (as is the case for the peak demand) or less than the previous stored value (as is
the case for the minimum demand), the old value is discarded and the new value is reported. Peak Demand and
Minimum Demand definitions are defined in Tables 5-22 and 5-23 The status of the update is reflected in Bits 9
and 10 of Register 40129. Please reference the 6X register configuration tables to configure energy demand
parameterization.
Demand Metering is reported within Table 5-?. The accumulated magnitudes are reported in 16 bit unsigned and
32 bit unsigned numerical values as indicated in the following table. The demands are reset by writing a reset
command to the 4X register, XXXX Bit X. Please reference Table 5-24 of this document for the control register
group and bit designation to reset this group of registers. Refer to Table 6 Register 4129 bit 9 which will indicate
that a new Peak Demand Value has been accumulated within this table.
Demand metering is calculated on a fixed demand window accumulation. The demands are based upon a time
window of 15, 30, or 60-minute calculation intervals. Refer to Table 5-26 within this document to reference the
procedure for setting the sliding demand window time base.
Demand Metering initiates at time = 0 which may be a unit power up, system reset via the front panel or through a
demand metering reset via the network as described in Table 5-24 of this document. It is not dependent upon the
time-of-day clock (TOD) within the unit. The TPU2000/2000R has an internal timer that is monitored to determine
the end of the selected interval (15, 30, or 60 minutes) and the start of the new interval.
Current (Ia, Ib, Ic, and In) and power (KW and KVAR) are calculated and integrated within the demand calculation
for that interval on a 32 cycle time period interval within the demand time window selected. The following figures
illustrate the method of calculating and reporting the Demand Values depending upon reporting of current or
energy.
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