ADE7880ACPZ-RL(RevA) View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

ADE7880ACPZ-RL
(Rev.:RevA)

Polyphase Multifunction Energy Metering IC with Harmonic Monitoring

Analog Devices 

Data Sheet

ADE7880

PGA1 BITS

GAIN[2:0]

REFERENCE

×1, ×2, ×4, ×8, ×16

IAP

DSP

AIGAIN[23:0]

INTEN BIT

CONFIG[0]

HPFEN BIT

CONFIG3[0] DIGITAL

INTEGRATOR

VIN

PGA1

IAN

ADC

HPF

VIN

+0.5V/GAIN

0x514791 =

+5,326,737

CURRENT CHANNEL

DATA RANGE

ZX DETECTION

LPF1

0x514791 =

CURRENT PEAK,

+5,326,737

OVERCURRENT

DETECT

0V

CURRENT RMS (IRMS)

CALCULATION

ZX SIGNAL

DATA RANGE

IAWV WAVEFORM

SAMPLE REGISTER

TOTAL/FUNDAMENTAL

ACTIVE AND REACTIVE

POWER CALCULATION

0xAEB86F =

–5,326,737

0x5A7540 =

+5,928,256

CURRENT CHANNEL

DATA RANGE AFTER

INTEGRATION

0V

0V

0V

–0.5V/GAIN

ANALOG INPUT RANGE

0xAEB86F =

–5,326,737

ANALOG OUTPUT RANGE

0xA58AC0 =

–5,928,256

Figure 41. Current Channel Signal Path

PGA2 BITS

GAIN[5:3]

REFERENCE

×1, ×2, ×4, ×8, ×16

IAP

DSP

NIGAIN[23:0]

ININTEN BIT

CONFIG3[3]

HPFEN BIT

CONFIG3[0] DIGITAL

INTEGRATOR

CURRENT RMS (IRMS)

CALCULATION

VIN

PGA2

IAN

ADC

HPF

Figure 42. Neutral Current Signal Path

INWV WAVEFORM

SAMPLE REGISTER

Current Waveform Gain Registers

There is a multiplier in the signal path of each phase and

neutral current. The current waveform can be changed by

±100% by writing a corresponding twos complement number to

the 24-bit signed current waveform gain registers (AIGAIN,

BIGAIN, CIGAIN, and NIGAIN). For example, if 0x400000 is

written to those registers, the ADC output is scaled up by 50%.

To scale the input by −50%, write 0xC00000 to the registers.

Equation 4 describes mathematically the function of the current

waveform gain registers.

Current Waveform =

ADC

Output

×

⎜⎜⎝⎛1

+

Content

of

Current

223

Gain

Register

⎟⎟⎠⎞

(4)

Changing the content of the AIGAIN, BIGAIN, CIGAIN, or

INGAIN registers affects all calculations based on its current;

that is, it affects the corresponding phase active/reactive/

apparent energy and current rms calculation. In addition,

waveform samples scale accordingly.

31

28 27

0000

24 23

0

24-BIT NUMBER

BITS[27:24] ARE BIT 23 IS A SIGN BIT

EQUAL TO BIT 23

Figure 43. 24-Bit xIGAIN Transmitted as 32-Bit Words

Current Channel HPF

The ADC outputs can contain a dc offset. This offset can create

errors in power and rms calculations. High-pass filters (HPFs)

are placed in the signal path of the phase and neutral currents

and of the phase voltages. If enabled, the HPF eliminates any dc

offset on the current channel. All filters are implemented in the

DSP and, by default, they are all enabled: Bit 0 (HPFEN) of the

CONFIG3[7:0] register is set to 1. All filters are disabled by

setting Bit 0 (HPFEN) to 0.

Note that the serial ports of the ADE7880 work on 32-, 16-, or

8-bit words, and the DSP works on 28 bits. The 24-bit AIGAIN,

BIGAIN, CIGAIN, and NIGAIN registers are accessed as 32-bit

registers with the four most significant bits (MSBs) padded with

0s and sign extended to 28 bits. See Figure 43 for details.

Rev. A | Page 27 of 104

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