Datasheet

Data Sheet ADE5166/ADE5169/ADE5566/ADE5569
Rev. D | Page 53 of 156
For calibration, a first measurement should be done on I
PA
by
setting the SEL_I_CH bits (Bits[5:4]) to 0b01 in the CALMODE
register (Address 0x3D). This measurement should be compared
to the measurement on I
PB
. Measuring I
PB
can be forced by setting
the SEL_I_CH bits (Bits[5:4]) to 0b10 in the CALMODE register
(Address 0x3D). The gain error between these two measurements
can be evaluated using the following equation:
Error (%) =
)(
)()(
PA
PA
PB
ItMeasuremen
ItMeasuremenItMeasuremen −
The two channels, I
PA
and I
PB
, can then be matched by writing
–Error(%)/(1 + Error(%)) × 2
12
to the IBGAIN register
(Address 0x1C). This matching adjustment is valid for all energy
measurements made by the ADE5166/ADE5169, including
active power, reactive power (the ADE5169 only), apparent
power, and I
rms
.
di/dt CURRENT SENSOR AND DIGITAL INTEGRATOR
(ADE5169/ADE5569 ONLY)
The di/dt sensor, a feature available for the ADE5169/ADE5569,
detects changes in the magnetic field caused by ac currents.
Figure 50 shows the principle of a di/dt current sensor.
MAGNETIC FIELD CREATED BY CURRENT
(DIRECTLY PROPORTIONAL TO CURRENT)
+ EMF (ELECTROMOTIVE FORCE)
– INDUCED BY CHANGES IN
MAGNETIC FLUX DENSITY (di/dt)
07411-026
Figure 50. Principle of a di/dt Current Sensor
The flux density of a magnetic field induced by a current is directly
proportional to the magnitude of the current. The changes in the
magnetic flux density passing through a conductor loop generate
an electromotive force (EMF) between the two ends of the loop.
The EMF is a voltage signal that is proportional to the di/dt of the
current. The voltage output from the di/dt current sensor is deter-
mined by the mutual inductance between the current-carrying
conductor and the di/dt sensor. The current signal needs to be
recovered from the di/dt signal before it can be used. An integrator
is, therefore, necessary to restore the signal to its original form.
The ADE5169/ADE5569 has a built-in digital integrator to recover
the current signal from the di/dt sensor. The digital integrator
on the current channel is switched off by default when the
ADE5169/ADE5569 is powered up. Setting the INTE bit (Bit 5)
in the MODE1 register (Address 0x0B) turns on the integrator.
Figure 51 to Figure 54 show the gain and phase response of the
digital integrator.
FREQUENCY (Hz)
10
GAIN (dB)
0
–10
–20
–30
–40
–50
100 1000
07411-027
Figure 51. Combined Gain Response of the Digital Integrator and
Phase Compensator
FREQUENCY (Hz)
10
2
10
3
FREQ
–88.0
PHASE (Degrees)
–88.5
–89.0
–89.5
–90.0
–90.5
07411-106
Figure 52. Combined Phase Response of the Digital Integrator and
Phase Compensator
FREQUENCY (Hz)
–1.0
–6.0
40 7045
GAIN (dB)
50 55 60 65
–1.5
–2.0
–2.5
–3.5
–4.5
–5.5
–3.0
–4.0
–5.0
07411-029
Figure 53. Combined Gain Response of the Digital Integrator and
Phase Compensator (40 Hz to 70 Hz)