Datasheet

Data Sheet ADE5166/ADE5169/ADE5566/ADE5569
Rev. D | Page 69 of 156
Reactive Energy Pulse Output
The ADE5169/ADE5569 provide all the circuitry with a pulse
output whose frequency is proportional to reactive power (see
the Energy-to-Frequency Conversion section). This pulse fre-
quency output uses the calibrated signal from the VA R GA I N
register output, and its behavior is consistent with the setting of the
reactive energy accu-mulation mode in the ACCMODE register
(Address 0x0F). The pulse output is active low and should
preferably be connected to an LED, as shown in Figure 80.
Line Cycle Reactive Energy Accumulation Mode
In line cycle reactive energy accumulation mode, the energy
accumulation of the ADE5169/ADE5569 can be synchronized
to the voltage channel zero crossing so that reactive energy can
be accumulated over an integral number of half-line cycles. The
advantages of this mode are similar to those described in the
Line Cycle Active Energy Accumulation Mode section.
In line cycle active energy accumulation mode, the ADE5169/
ADE5569 accumulate the reactive power signal in the LVARHR
register (Address 0x06) for an integral number of line cycles, as
shown in Figure 75. The number of half-line cycles is specified
in the LINCYC register (Address 0x12). The ADE5169 /ADE5569
can accumulate active power for up to 65,535 half-line cycles.
Because the reactive power is integrated on an integral number
of line cycles, the CYCEND flag (Bit 2) in the Interrupt Status 3
SFR (MIRQSTH, Address 0xDE) is set at the end of a reactive
energy accumulation line cycle. If the CYCEND enable bit (Bit 2)
in the Interrupt Enable 3 SFR (MIRQENH, Address 0xDB) is set,
the 8052 core has a pending ADE interrupt. The ADE interrupt
stays active until the CYCEND status bit is cleared (see the Energy
Measurement Interrupts section). Another calibration cycle starts
as soon as the CYCEND flag is set. If the LVARHR register
(Address 0x06) is not read before a new CYCEND flag is set, the
LVARHR register is overwritten by a new value.
When a new half-line cycle is written in the LINCYC register
(Address 0x12), the LVARHR register is reset, and a new
accumulation starts at the next zero crossing. The number of
half-line cycles is then counted internally until the value program-
med in LINCYC is reached. This implementation provides a valid
measurement at the first CYCEND interrupt after writing to the
LINCYC register. The line reactive energy accumulation uses
the same signal path as the reactive energy accumulation. The
LSB size of these two registers is equivalent.
LPF1
+
+
ACCUMULATE REACTIVE
ENERGY IN INTERNAL
REGISTER AND UPDATE
THE LVARHR REGISTER
AT THE END OF LINCYC
HALF-LINE CYCLES
OUTPUT
FROM
LPF2
FROM VOLTAGE
CHANNEL ADC
23 0
LINCYC[15:0]
48 0
%
ZERO-CROSSING
DETECTION
LVARHR[23:0]
CALIBRATION
CONTROL
VARDIV[7:0]VAROS[15:0]
VARGAIN[11:0]
TO
DIGITAL-TO-FREQUENCY
CONVERTER
07411-050
Figure 75. Line Cycle Reactive Energy Accumulation Mode