Datasheet

Data Sheet ADE5166/ADE5169/ADE5566/ADE5569
Rev. D | Page 63 of 156
Figure 67 shows this energy accumulation for full-scale signals
(sinusoidal) on the analog inputs. The three displayed curves
illustrate the minimum period of time it takes the energy register
to roll over when the active power gain register contents are
0x7FF, 0x000, and 0x800. The watt gain register is used to carry
out power calibration in the ADE5166/ADE5169/ADE5566/
ADE5569. As shown, the fastest integration time occurs when
the watt gain register is set to maximum full scale, that is, 0x7FF.
0x00 0000
0x7F FFFF
0x3F FFFF
0x40 0000
0x80 0000
WATTHR[23:0]
6.823.41 10.2
13.7
TIME (Minutes)
WGAIN = 0x7FF
WGAIN = 0x000
WGAIN = 0x800
07411-042
Figure 67. Energy Register Rollover Time for Full-Scale Power
(Minimum and Maximum Power Gain)
Note that the energy register contents roll over to full-scale negative
(0x800000) and continue to increase in value when the power or
energy flow is positive (see Figure 67). Conversely, if the power is
negative, the energy register underflows to full-scale positive
(0x7FFFFF) and continues to decrease in value.
Using the Interrupt Enable 2 SFR (MIRQENM, Address 0xDA),
the ADE5166/ADE5169/ADE5566/ADE5569 can be configured
to issue an ADE interrupt to the 8052 core when the active
energy register is half full (positive or negative) or when an
overflow or underflow occurs.
Integration Time Under Steady Load—Active 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 WGAIN register (Address 0x1D) set to
0x000, the average word value from each LPF2 is 0xCCCCD
(see Figure 64). The maximum positive value that can be stored in
the internal 49-bit register is 2
48
(or 0xFFFF FFFF FFFF) before it
overflows. The integration time under these conditions when
WDIV = 0 is calculated in the following equation:
Time =
min82.6sec6.409μs22.1
xCCCCD0
FFFFFFFFxFFFF0
==×
(14)
When WDIV is set to a value other than 0, the integration time
varies, as shown in Equation 15.
Time = Time
WDIV = 0
× WDIV (15)
Active Energy Accumulation Modes
Watt Signed Accumulation Mode
The ADE5166/ADE5169/ADE5566/ADE5569 active energy
default accumulation mode is a watt-signed accumulation that
is based on the active power information.
Watt Positive-Only Accumulation Mode
The ADE5166/ADE5169/ADE5566/ADE5569 are placed in watt
positive-only accumulation mode by setting the POAM bit (Bit 1)
in the ACCMODE register (Address 0x0F). In this mode, the
energy accumulation is done only for positive power, ignoring
any occurrence of negative power above or below the no load
threshold (see Figure 68). The CF pulse also reflects this accumu-
lation method when in this mode. The default setting for this
mode is off. Detection of transitions in the direction of power
flow and detection of no load threshold are active in this mode.
POSPOS
INTERRUPT STATUS REGISTERS
NEG
APSIGN FLAG
NO LOAD
THRESHOLD
ACTIVE POWER
NO LOAD
THRESHOLD
ACTIVE ENERGY
07411-043
Figure 68. Energy Accumulation in Positive-Only Accumulation Mode
Watt Absolute Accumulation Mode
The ADE5166/ADE5169/ADE5566/ADE5569 are placed in watt
absolute accumulation mode by setting the ABSAM bit (Bit 0) in
the ACCMODE register (Address 0x0F). In this mode, the
energy accumulation is done using the absolute active power,
ignoring any occurrence of power below the no load threshold
(see Figure 69). The CF pulse also reflects this accumulation
method when in this mode. The default setting for this mode is
off. Detection of transitions in the direction of power flow and
detection of no load threshold are active in this mode.