ade7169f16 Analog Devices, Inc., ade7169f16 Datasheet - Page 50

• Manufacturer Part Number: ade7169f16
• Description: Single-phase Energy Measurement Ic With 8052 Mcu, Rtc And Lcd Driver
• Manufacturer: Analog Devices, Inc.

ADE7169F16
The rms signals can be read from the waveform register by
setting the WAVMODE register (0x0D) and setting the WFSM
bit in the Interrupt Enable Register 3 SFR (MIRQENH, 0xDB).
Like the current and voltage channels waveform sampling
modes, the waveform date is available at sample rates of 27.9
kSPS, 14 kSPS, 7 kSPS, or 3.5 kSPS.
Important: When the current input is larger than 40% of Full
scale, the Irms waveform sample register does not represent the
true rms value processed. The rms value processed with this
level of input is larger than the 24 bit read by the waveform
register making the value read truncated on the high end.
Current Channel RMS Calculation
The ADE7169F16 simultaneously calculates the rms values for
the Current and Voltage channel in different registers. The
current channel rms calculation is done on the channel selected
by SEL_I_CH bits in the CALMODE register (0x3D). Figure 35
shows the detail of the signal processing chain for the rms
calculation on the current channel. The current channel rms
value is processed from the samples used in the current channel
Current channel RMS Offset Compensation
The ADE7169F16 incorporates a current channel rms offset
compensation register (IRMSOS). This is a 12-bit signed
register that can be used to remove offset in the current channel
rms calculation. An offset could exist in the rms calculation due
to input noises that are integrated in the dc component of V
The offset calibration allows the content of the IRMS register to
IA
IB
HPF
HPF
INTEGRATOR*
DIGITAL
MODE1[5]
dt
Figure 35. Current channel RMS Signal Processing
HPF1
0xD70A3E
0xD487B0
Rev. PrD | Page 50 of 140
0x28F5C2
0x2B7850
0x000000
0x000000
2
(t).
60Hz
24
CURRENT CHANNEL
WAVEFORM
DATA RANGE WITH
INTEGRATOR ON (60Hz)
CURRENT CHANNEL
WAVEFORM
DATA RANGE WITH
INTEGRATOR OFF
waveform sampling mode. The current channel rms value is
stored in an unsigned 24-bit register (IRMS). One LSB of the
current channel rms register is equivalent to one LSB of a
current channel waveform sample.
The update rate of the current channel rms measurement is
MCLK/5. To minimize noise in the reading of the register, the
Irms register can also be configured to be updated only with the
zero crossing of the voltage input. This configuration is done by
setting ZXRMS bit in the MODE2 register (0x0C).
With the specified full-scale analog input signal of 0.5 V, the
ADC produces an output code that is approximately
±0d2,684,354—see the Current Channel ADC section. The
equivalent rms value of a full-scale ac signal is 0d1,898,124
(0x1CF68C). The current rms measurement provided in the
ADE7169F16 is accurate to within 0.5% for signal input
between full scale and full scale/1000. The conversion from the
register value to amps must be done externally in the
microprocessor using an amps/LSB constant.
be maintained at 0 when no input is present on current channel.
One LSB of the current channel rms offset is equivalent to
16,384 LSB of the square of the current channel rms register.
Assuming that the maximum value from the current channel
rms calculation is 0d1,898,124 with full-scale ac inputs, then 1
LSB of the current channel rms offset represents 0.23% of
measurement error at –60 dB down of full scale.
LPF3
sgn
2
25
2
26
IRMSOS[11:0]
2
27
+
Preliminary Technical Data
2
18
2
17
2
16
24
0x00
I
RMS
IRMS[23:0]
(t)