ade7169f16 Analog Devices, Inc., ade7169f16 Datasheet - Page 62

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

ADE7169F16
Note that the apparent energy register is unsigned. By setting the
VAEHF and VAEOF bits in the Interrupt Enable Register 2 SFR
(MIRQENM, 0xDA), the ADE7169F16 can be configured to
issue an ADE interrupt to the 8052 core when the apparent
energy register is half full or when an overflow occurs. The half
full interrupt for the unsigned apparent energy register is based
on 24 bits as opposed to 23 bits for the signed active energy
register.
Integration Times under Steady Load
As mentioned in the last section, the discrete time sample
period (T) for the accumulation register is 1.22 µs (5/MCLK).
With full-scale sinusoidal signals on the analog inputs and the
VAGAIN register set to 0x000, the average word value from
apparent power stage is 0x1A36E2—see the section. The
maximum value that can be stored in the apparent energy
register before it overflows is 2
word value is added to the internal register, which can store 2
or 0xFFFF,FFFF,FFFF before it overflows. Therefore, the
integration time under these conditions with VADIV = 0 is
calculated as follows:
When VADIV is set to a value different from 0, the integration
APPARENT POWER
Time =
T
Figure 50. ADE7169F16 Apparent Energy Calculation
0
xFFFF,
APPARENT POWER
TIME (nT)
SIGNAL = P
0
xD
FFFF,
+
055
+
FFFF
48
48
23
24
VADIV
VAHR[23:0]
or 0xFF,FFFF. The average
× 1.22 µs = 199 s = 3.33 min (32)
APPARENT POWER ARE
ACCUMULATED (INTEGRATED) IN
THE APPARENT ENERGY REGISTER
%
0
Rev. PrD | Page 62 of 140
0
0
48
time varies, as shown in Equation 33.
Apparent energy Pulse output
ADE7169F16 also provides all the circuitry to have a pulse
output those frequency is proportional to apparent power – see
Energy-to-Frequency Conversion section. This pulse frequency
output uses the calibrated signal after VAGAIN. This output can
also be used to output a pulse those frequency is proportional to
Irms.
The pulse output is active low and should be preferably
connected to an LED as shown on
Line Apparent Energy Accumulation
The ADE7169F16 is designed with a special apparent energy
accumulation mode, which simplifies the calibration process.
By using the on-chip zero-crossing detection, the ADE7169F16
accumulates the apparent power signal in the LVAHR register
for an integral number of half cycles, as shown in Figure 51. The
line apparent energy accumulation mode is always active.
The number of half line cycles is specified in the LINCYC
register, which is an unsigned 16-bit register. The ADE7169F16
can accumulate apparent power for up to 65535 combined half
cycles. Because the apparent power is integrated on the same
integral number of line cycles as the line active and reactive
energy register, these values can be compared easily. The
energies are calculated more accurately because of this precise
timing control and provide all the information needed for
reactive power and power factor calculation. At the end of an
energy calibration cycle, the CYCEND flag in the Interrupt
Status Register 3 SFR (MIRQSTH, 0xDE) is set. If the CYCEND
enable bit in the Interrupt Enable Register 3 SFR (MIRQENH,
0xDB) is enabled, the 8052 core has a pending ADE interrupt.
As for LWATTHR, when a new half line cycles is written in
LINECYC register, the LVAHR register is reset and a new
accumulation start at the next zero-crossing. The number of
half line cycles is then counted until LINCY is reached. This
implementation provides a valid measurement at the first
CYCEND interrupt after writing to the LINCYC register. The
line apparent energy accumulation uses the same signal path as
the apparent energy accumulation. The LSB size of these two
registers is equivalent.
Time = Time
WDIV = 0
Preliminary Technical Data
× VADIV
Figure 53
.
(33)