ade7169f16 Analog Devices, Inc., ade7169f16 Datasheet - Page 58

• Manufacturer Part Number: ade7169f16
• Description: Single-phase Energy Measurement Ic With 8052 Mcu, Rtc And Lcd Driver
• Manufacturer: Analog Devices, Inc.

ADE7169F16
(default), the VARSIGN flag in the Interrupt Status Register 1
SFR (MIRQSTL, 0xDC) will be set when a transition from
positive to negative reactive power has occurred.
When VARSIGN in the ACCMODE register (0x0F) is set, the
VARSIGN flag in the Interrupt Status Register 1 SFR
(MIRQSTL, 0xDC) will be set when a transition from negative
to positive reactive power has occurred.
Reactive power no-Load detection
The ADE7169F16 includes a no-load threshold feature on the
reactive energy that eliminates any creep effects in the meter.
The ADE7169F16 accomplishes this by not accumulating
reactive energy if the multiplier output is below the no-load
Reactive Energy Calculation
As for active energy, the ADE7169F16 achieves the integration
of the reactive power signal by continuously accumulating the
reactive power signal in an internal non-readable 49-bit energy
register. The reactive energy register (VARHR[23:0]) represents
the upper 24 bits of this internal register.
The discrete time sample period (T) for the accumulation
register in the ADE7169F16 is 1.22µs (5/MCLK). As well as
calculating the energy, this integration removes any sinusoidal
components that might be in the active power signal. Figure 45
shows this discrete time integration or accumulation. The
reactive power signal in the waveform register is continuously
added to the internal reactive energy register.
The reactive Energy accumulation depends on the setting of the
SAVARM and ABSVARM bits in the ACCMODE register
(0x0F). When both bits are cleared, the addition is signed and
CURRENT
CHANNEL
VOLTAGE
CHANNEL
HPF
PHCAL[7:0]
SHIFTING FILTER
90° PHASE
2
T
REACTIVE POWER
LPF2
CLKIN
sgn
Figure 45. ADE7169F16 Reactive Energy Calculation
SIGNAL
5
TIME (nT)
VAROS[15:0]
2
6
2
+
5
+
Rev. PrD | Page 58 of 140
2
WAVEFORM
REGISTER
-6
VALUES
2
-7
2
-8
FOR WAVEF0RM
VARGAIN[11:0]
SAMPLING
threshold. When the reactive power is below the no-load
threshold, the RNOLOAD flag in the Interrupt Status Register 1
SFR (MIRQSTL, 0xDC) is set. If the RNOLOAD bit is set in the
Interrupt Enable Register 1 SFR (MIRQENL, 0xD9), the 8052
core has a pending ADE interrupt. The ADE interrupt stays
active until the RNOLOAD status bit is cleared—see Energy
measurement interrupts section.
The No-load threshold level is selectable by setting bits
RNOLOAD in the NLMODE register (0x0E). Setting these bits
to 0b00 disable the no-load detection and setting them to 0b01,
0b10 or 0b11 set the no-load detection threshold to 0.015%,
0.0075% and 0.0037% of the full-scale output frequency of the
multiplier respectively.
therefore negative energy is subtracted from the reactive energy
contents. When both bits are set, the ADE7169F16 is set to be
in the more restrictive mode, the Absolute Accumulation mode.
When SAVARM bit in the ACCMODE register (0x0F) is set,
the reactive power is accumulated depending on the sign of the
active power. When active power is positive, the reactive power
is added as it is to the reactive energy register. When active
power is negative, the reactive power is subtracted to the
reactive energy accumulator – see VAR anti-tamper
accumulation mode.
When ABSVARM bit in the ACCMODE register (0x0F) is set,
the absolute reactive power is used for the reactive energy
accumulation—see the VAR absolute accumulation mode
section.
The output of the multiplier is divided by VARDIV. If the value
in the VARDIV register is equal to 0, then the internal reactive
DIGITAL TO FREQUENCY
VARDIV[7:0]
%
CONVERTER
TO
+
+
48
23
Preliminary Technical Data
VARHR[23:0]
OUTPUTS FROM THE LPF2 ARE
ACCUMULATED (INTEGRATED) IN
THE INTERNAL REACTIVE ENERGY REGISTER
0
UPPER 24 BITS ARE
ACCESSIBLE THROUGH
VARHR[23:0] REGISTER
0