ADE7878 datasheet(29/92 Pages) AD

29 / 92 page

ADE7878

Rev. 0 | Page 29 of 92

AVGAIN[23:0]

REFERENCE

HPFDIS

[23:0]

DSP

TOTAL/FUNDAMENTAL

ACTIVE AND REACTIVE

POWER CALCULATION

VOLTAGE PEAK,

OVERVOLTAGE,

SAG DETECT

VAWV WAVEFORM

SAMPLE REGISTER

CURRENT RMS (VRMS)

CALCULATION

HPF

ADC

PGA3

VAP

ZX DETECTION

PGA3 BITS

GAIN[8:6]

×1, ×2, ×4, ×8, ×16

VIN

ANALOG INPUT RANGE

ANALOG OUTPUT RANGE

0x5A7540 =

+5,928,256

ZX SIGNAL

DATA RANGE

0xA58AC0 =

–5,928,256

0x5A7540 =

+5,928,256

VOLTAGE CHANNEL

DATA RANGE

0xA58AC0 =

–5,928,256

+0.5V/GAIN

–0.5V/GAIN

LPF1

Figure 38. Voltage Channel Datapath

CHANGING PHASE VOLTAGE DATAPATH

The ADE7878 can direct one phase voltage input to the computa-

tional datapath of another phase. For example, Phase A voltage can

be introduced in the Phase B computational datapath, which

means all powers computed by the ADE7878 in Phase B are based

on Phase A voltage and Phase B current.

Bits[9:8] (VTOIA[1:0]) of the CONFIG[15:0] register manage

the Phase A voltage measured at the VA pin. If VTOIA[1:0] = 00

(default value), the voltage is directed to the Phase A computa-

tional datapath, if VTOIA[1:0] = 01, the voltage is directed to

the Phase B path, and if VTOIA[1:0] = 10, the voltage is directed

to the Phase C path. If VTOIA[1:0] = 11, the ADE7878 behaves

as if VTOIA[1:0] = 00.

Bits[11:10] (VTOIB[1:0]) of the CONFIG[15:0] register manage

the Phase B voltage measured at the VB pin. If VTOIB[1:0] = 00

(default value), the voltage is directed to the Phase B computa-

tional datapath, if VTOIB[1:0] = 01, the voltage is directed to

the Phase C path, and if VTOIB[1:0] = 10, the voltage is directed to

the Phase A path. If VTOIB[1:0] = 11, the ADE7878 behaves as

if VTOIB[1:0] = 00.

Bits[3:12] (VTOIC[1:0]) of the CONFIG[15:0] register manage

the Phase C voltage measured at the VC pin. If VTOIC[1:0] = 00

(default value), the voltage is directed to Phase C computational

datapath, if VTOIC[1:0] = 01, the voltage is directed to the

Phase A path, and if VTOIC[1:0] = 10, the voltage is directed to

the Phase B path. If VTOIC[1:0] = 11, the ADE7878 behaves as

if VTOIC[1:0] = 00.

PHASE A

COMPUTATIONAL

DATA PATH

PHASE B

COMPUTATIONAL

DATA PATH

PHASE C

COMPUTATIONAL

DATA PATH

VTOIA[1:0] = 01,

PHASE A VOLTAGE

DIRECTED

TO PHASE B

VTOIB[1:0] = 01,

PHASE B VOLTAGE

DIRECTED

TO PHASE C

VTOIC[1:0] = 01,

PHASE C VOLTAGE

DIRECTED

TO PHASE A

CPHCAL

BPHCAL

APHCAL

Figure 39. Phase Voltages Used in Different Datapaths

Figure 39 presents the case in which Phase A voltage is used in

the Phase B datapath, Phase B voltage is used in the Phase C

datapath, and Phase C voltage is used in the Phase A datapath.

POWER QUALITY MEASUREMENTS

Zero-Crossing Detection

The ADE7878 has a zero-crossing (ZX) detection circuit on the

phase current and voltage channels. The neutral current

datapath does not contain a zero-crossing detection circuit.

Zero-crossing events are used as a time base for various power

quality measurements and in the calibration process.

A zero crossing is generated from the output of LPF1. The low-

pass filter is intended to eliminate all harmonics of 50 Hz and

60 Hz systems and help identify the zero-crossing events on the

fundamental components of both current and voltage channels.

ADE7878 数据表(PDF) 29 Page - Analog Devices

ADE7878 数据表(HTML) 29 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92

数据表下载

链接网址

ADE7878 数据表(PDF) 29 Page - Analog Devices

ADE7878 数据表(HTML) 29 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92

数据表 下载

链接网址

数据表下载