ADE5166_08 AD [Analog Devices], ADE5166_08 Datasheet - Page 47

• Manufacturer Part Number: ADE5166_08
• Description: Single-Phase Energy Measurement IC with 8052 MCU, RTC, and LCD Driver
• Manufacturer: AD [Analog Devices]

For calibration, a first measurement should be done on I
setting the SEL_I_CH bits to 0b01 in the CALMODE register
(Address 0x3D). This measurement should be compared to the
measurement on I
SEL_I_CH bits to 0b10 in the CALMODE register (Address 0x3D).
The gain error between these two measurements can be evaluated
using the following equation:
The two channels, I
–Error(%)/(1 + Error(%)) × 2
(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
di/dt CURRENT SENSOR AND DIGITAL INTEGRATOR
(ADE5169)
A di/dt sensor, a feature available for the ADE5169, detects changes
in the magnetic field caused by ac currents. Figure 46 shows the
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 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
is powered up. Setting the INTE bit (Bit 5) in the MODE1 register
(Address 0x0B) turns on the integrator. Figure 47 to Figure 50
show the gain and phase response of the digital integrator.
Error
( )
%
=
Figure 46. Principle of a di/dt Current Sensor
Measuremen
PB
. Measuring I
PA
Measuremen
rms
and I
t
.
( )
I
MAGNETIC FIELD CREATED BY CURRENT
(DIRECTLY PROPORTIONAL TO CURRENT)
B
PB
−
, can then be matched by writing
Measuremen
12
I t
to the IBGAIN register
( )
PB
A
can be forced by setting the
+ EMF (ELECTROMOTIVE FORCE)
– INDUCED BY CHANGES IN
MAGNETIC FLUX DENSITY (di/dt)
I t
( )
A
PA
by
Rev. 0 | Page 47 of 148
Figure 48. Combined Phase Response of the Digital Integrator and
Figure 47. Combined Gain Response of the Digital Integrator and
Figure 49. Combined Gain Response of the Digital Integrator and
–
–1.5
–2.0
–2.5
–3.0
–3.5
–4.0
–4.5
–5.0
–5.5
–6.0
–88.0
–88.5
–89.0
–89.5
–90.0
–90.5
–10
–20
–30
–40
–50
1.0
10
0
40
45
Phase Compensator (40 Hz to 70 Hz)
100
Phase Compensator
Phase Compensator
10
50
2
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQ
55
ADE5166/ADE5169
60
1000
10
3
65
70