ade7518 Analog Devices, Inc., ade7518 Datasheet - Page 56

• Manufacturer Part Number: ade7518
• Description: Single-phase Energy Measurement Ic With 8052 Mcu, Rtc, And Lcd Driver
• Manufacturer: Analog Devices, Inc.

ADE7518
Integration Time Under Steady Load: Reactive Energy
As mentioned in the Active Energy Calculation 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 VARGAIN and VARDIV registers set to
0x000, the integration time before the reactive energy register
overflows is calculated in Equation 24.
When VARDIV is set to a value other than 0, the integration
time varies, as shown in Equation 25.
Reactive Energy Accumulation Modes
VAR-Signed Accumulation Mode
The ADE7518 reactive energy default accumulation mode is a
signed accumulation based on the reactive power information.
VAR Antitamper Accumulation Mode
The ADE7518 is placed in VAR antitamper accumulation mode
by setting the SAVARM bit in the ACCMODE register (0x0F). In
this mode, 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
from the reactive energy accumulator (see Figure 59). The CF
pulse also reflects this accumulation method when in this mode.
The default setting for this mode is off. Transitions in the direction
of power flow and no load threshold are active in this mode.
Time =
Time
0xFFFF,
=
0xCCCCD
Time
FFFF,
WDIV
= 0
FFFF
×
VARDIV
×
. 1
22
μ
s
=
409
6 .
sec
=
. 6
82
min
Rev. 0 | Page 56 of 128
(24)
(25)
REACTIVE ENERGY
REACTIVE POWER
ACTIVE POWER
APSIGN FLAG
THRESHOLD
THRESHOLD
THRESHOLD
THRESHOLD
NO LOAD
NO LOAD
NO LOAD
NO LOAD
Figure 59. Reactive Energy Accumulation in
Antitamper Accumulation Mode
INTERRUPT STATUS REGISTERS
POS
NEG
POS