ADE7753
ENERGIES SCALING
The ADE7753 provides measurements of active, reactive, and
apparent energies. These measurements do not have the same
scaling and thus cannot be compared directly to each other.
Table 10. Energies Scaling
PF = 1
Integrator On at 50 Hz
Active
Wh
Reactive
0
Apparent
Wh × 0.848
Integrator Off at 50 Hz
Active
Wh
Reactive
0
Apparent
Wh × 0.848
Integrator On at 60 Hz
Active
Wh
Reactive
0
Apparent
Wh × 0.827
Integrator Off at 60 Hz
Active
Wh
Reactive
0
Apparent
Wh × 0.827
PF = 0.707
Wh × 0.707
Wh × 0.508
Wh × 0.848
Wh × 0.707
Wh × 0.245
Wh × 0.848
Wh × 0.707
Wh × 0.610
Wh × 0.827
Wh × 0.707
Wh × 0.204
Wh × 0.827
PF = 0
0
Wh × 0.719
Wh × 0.848
0
Wh × 0.347
Wh × 0.848
0
Wh × 0.863
Wh × 0.827
0
Wh × 0.289
Wh × 0.827
CALIBRATING AN ENERGY METER BASED ON THE
ADE7753
The ADE7753 provides gain and offset compensation for active
and apparent energy calibration. Its phase compensation corrects
phase error in active, apparent and reactive energy. If a shunt is
used, offset and phase calibration may not be required. A
reference meter or an accurate source can be used to calibrate
the ADE7753.
When using a reference meter, the ADE7753 calibration output
frequency, CF, is adjusted to match the frequency output of the
reference meter. A pulse output is only provided for the active
energy measurement in the ADE7753. If it is desired to use a
reference meter for calibrating the VA and VAR, then additional
code would have to be written in a microprocessor to produce a
pulsed output for these quantities. Otherwise, VA and VAR
calibration require an accurate source.
The ADE7753 provides a line cycle accumulation mode for
calibration using an accurate source. In this method, the active
energy accumulation rate is adjusted to produce a desired CF
frequency. The benefit of using this mode is that the effect of
the ripple noise in the active energy is eliminated. Up to 65535
half line cycles can be accumulated, thus providing a stable
energy value to average. The accumulation time is calculated
from the line cycle period, measured by the ADE7753 in the
PERIOD register, and the number of half line cycles in the
accumulation, fixed by the LINECYC register.
Current and voltage rms offset calibration removes any apparent
energy offset. A gain calibration is also provided for apparent
energy. Figure 79 shows an optimized calibration flow for active
energy, rms, and apparent energy.
Active and apparent energy gain calibrations can take place
concurrently, with a read of the accumulated apparent energy
register following that of the accumulated active energy register.
Figure 78 shows the calibration flow for the active energy
portion of the ADE7753.
WATT GAIN CALIBRATION
WATT OFFSET CALIBRATION
PHASE CALIBRATION
Figure 78. Active Energy Calibration
02875-A-005
The ADE7753 does not provide means to calibrate reactive
energy gain and offset. The reactive energy portion of the
ADE7753 can be calibrated externally, through a MCU.
WATT/VA GAIN CALIBRATION
RMS CALIBRATION
WATT OFFSET CALIBRATION
Figure 79. Apparent and Active Energy Calibration
PHASE CALIBRATION
02875-A-002
Rev. C | Page 38 of 60