Datasheet

ADE7880 Data Sheet
Rev. A | Page 46 of 104
Bits[8:6] (REVAPC, REVAPB, and REVAPA, respectively) in the
STATUS0 register are set when a sign change occurs in the
power selected by Bit 6 (REVAPSEL) in the ACCMODE
register.
Bits[2:0] (CWSIGN, BWSIGN, and AWSIGN, respectively) in
the PHSIGN register are set simultaneously with the REVAPC,
REVAPB, and REVAPA bits. They indicate the sign of the
power. When they are 0, the corresponding power is positive.
When they are 1, the corresponding power is negative.
Bit REVAPx of STATUS0 and Bit xWSIGN in the PHSIGN
register refer to the total active power of Phase x, the power type
being selected by Bit 6 (REVAPSEL) in the ACCMODE register.
Interrupts attached to Bits[8:6] (REVAPC, REVAPB, and
REVAPA, respectively) in the STATUS0 register can be enabled
by setting Bits[8:6] in the MASK0 register. If enabled, the
IRQ0
pin is set low, and the status bit is set to 1 whenever a change of
sign occurs. To find the phase that triggered the interrupt, the
PHSIGN register is read immediately after reading the STATUS0
register. Next, the status bit is cleared and the
IRQ0
pin is returned
to high by writing to the STATUS0 register with the corresponding
bit set to 1.
Active Energy Calculation
As previously stated, power is defined as the rate of energy flow.
This relationship can be expressed mathematically as
d
t
dEnergy
Power =
(24)
Conversely, energy is given as the integral of power, as follows:
()
dttpEnergy
∫
=
(25)
Total and fundamental active energy accumulations are always
signed operations. Negative energy is subtracted from the active
energy contents.
INTERNAL
ACCUMULATOR
THRESHOLD
HPFEN BIT
CONFIG3[0]
HPF
DIGITAL SIGNAL PROCESSOR
AIGAIN
AVGAIN
HPFEN BIT
CONFIG3[0]
INTEN BIT
CONFIG[0]
HPF
VA
IA
LPF
APGAIN AWATTOS
APHCAL
2
4
AWATT
:
WTHR
34 27 26 0
0
32-BIT REGISTER
AWATTHR[31:0]
REVAPA BIT IN
STATUS0[31:0]
10193-049
Figure 74. Total Active Energy Accumulation