ade7880 Analog Devices, Inc., ade7880 Datasheet - Page 64

• Manufacturer Part Number: ade7880
• Description: Polyphase Multifunction Energy Metering Ic With Harmonic Monitoring
• Manufacturer: Analog Devices, Inc.

ADE7880
cleared to 0, the default state, no latch occurs. The process is
available even if the CFx output is not enabled by the CFxDIS
bits in the CFMODE register.
Energy registers and CF Outputs for Various
Accumulation Modes
Bits[1:0] (WATTACC[1:0]) in the ACCMODE register deter-
mine the accumulation modes of the total and fundamental active
powers when signals proportional to the active powers are chosen
at the CFx pins (the CFxSEL[2:0] bits in the CFMODE register
equal 000 or 011). They also determine the accumulation modes
of the watt-hour energy registers (AWATTHR, BWATTHR,
CWATTHR, AFWATTHR, BFWATTHR and CFWATTHR).
When WATTACC[1:0] = 00 (the default value), the active powers
are sign accumulated in the watt-hour registers and before entering
the energy-to-frequency converter. Figure 65 shows how signed
active power accumulation works. In this mode, the CFx pulses
synchronize perfectly with the active energy accumulated in
xWATTHR registers because the powers are sign accumulated in
both data paths.
When WATTACC[1:0]=01, the active powers are accumulated
in positive only mode. When the powers are negative, the watt-
hour energy registers are not accumulated. CFx pulses are
generated based on signed accumulation mode. In this mode,
the CFx pulses do not synchronize perfectly with the active
energy accumulated in xWATTHR registers because the powers
are accumulated differently in each data path. Figure 66 shows
how positive only active power accumulation works.
WATTACC[1:0]=10 setting is reserved and the ADE7880
behaves identically to the case when WATTACC[1:0]=00.
When WATTACC[1:0] = 11, the active powers are accumulated
in absolute mode. When the powers are negative, they change
sign and accumulate together with the positive power in the
watt-hour registers and before entering the energy-to-frequency
ACTIVE ENERGY
ACTIVE POWER
THRESHOLD
THRESHOLD
REVAPx BIT
xWSIGN BIT
IN STATUS0
IN PHSIGN
NO-LOAD
NO-LOAD
Figure 65. Active Power Signed Accumulation Mode
SIGN = POSITIVE
APNOLOAD
POS
NEG
POS
NEG
Rev. PrE | Page 64 of 103
converter. In this mode, the CFx pulses synchronize perfectly
with the active energy accumulated in xWATTHR registers
because the powers are accumulated in the same way in both data
paths. Figure 67 shows how absolute active power accumulation
works.
Bits[3:2] (VARACC[1:0]) in the ACCMODE register determine the
accumulation modes of the fundamental reactive powers when
signals proportional to the fundamental reactive powers are
chosen at the CFx pins (the CFxSEL[2:0] bits in the CFMODE
register equal 100). When VARACC[1:0] = 00, the default value,
the fundamental reactive powers are sign accumulated in the
var-hour energy registers and before entering the energy-to-
frequency converter. Figure 68 shows how signed fundamental
reactive power accumulation works. In this mode, the CFx
pulses synchronize perfectly with the fundamental reactive
energy accumulated in the xFVARHR registers because the
powers are sign accumulated in both data paths.
VARACC[1:0]=01 setting is reserved and ADE7880 behaves
identically to the case when VARACC[1:0]=00.
When VARACC[1:0] = 10, the fundamental reactive powers are
accumulated depending on the sign of the corresponding active
power in the var-hour energy registers and before entering the
energy-to-frequency converter. If the fundamental active power
is positive or considered 0 when lower than the no load
threshold, the fundamental reactive power is accumulated as is.
If the fundamental active power is negative, the sign of the
fundamental reactive power is changed for accumulation. Figure
69 shows how the sign adjusted fundamental reactive power
accumulation mode works. In this mode, the CFx pulses
synchronize perfectly with the fundamental reactive energy
accumulated in xFVARHR registers because the powers are
accumulated in the same way in both data paths.
THRESHOLD
THRESHOLD
in STATUS0
REVAPx bit
xWSIGN bit
in PHSIGN
NO-LOAD
NO-LOAD
ENERGY
POWER
ACTIVE
ACTIVE
Figure 66. Active Power Positive Only Accumulation Mode
SIGN=POSITIVE
APNOLOAD
Preliminary Technical Data
POS
NEG
POS
NEG