ADE7913 datasheet(23/44 Pages) AD

23 / 44 page

Data Sheet

ADE7912/ADE7913

Rev. 0 | Page 23 of 44

APPLICATIONS INFORMATION

ADE7912/ADE7913 IN POLYPHASE ENERGY

METERS

The ADE7912/ADE7913 are designed for use in 3-phase

energy metering systems in which two, three, or four

ADE7912/ADE7913 devices are managed by a master device

containing an SPI interface, usually a microcontroller.

Figure 33. Phase A ADE7912/ADE7913 Current and Voltage Sensing

Figure 33 shows the Phase A of a 3-phase energy meter. The

Phase A current, IA, is sensed with a shunt. A pole of the shunt

is connected to the IM pin of the ADE7912/ADE7913 and

becomes the ground, GNDISO (Pin 10), of the isolated side of the

ADE7912/ADE7913. The Phase A to neutral voltage, VAN, is

sensed with a resistor divider, and the VM pin is also connected

to the IM and GNDISO pins. Note that the voltages measured by

the ADCs of the ADE7912/ADE7913 are opposite to VAN and

IA, a classic approach in single-phase metering. The other

ADE7912/ADE7913 devices that monitor Phase B and Phase C

are connected in a similar way.

The V2P voltage channel is intended to measure an auxiliary

voltage, and it is available only on the ADE7913. If V2P is not

used, as is the case of the ADE7912, connect V2P to VM.

Figure 34. Neutral Line and Neutral to Earth Voltage Monitoring

with the ADE7912/ADE7913

Figure 34 shows how the ADE7912/ADE7913 inputs are

connected when the neutral line of a 3-phase system is

monitored. The neutral current is sensed using a shunt and the

voltage across the shunt is measured at the fully differential

inputs, IP and IM. The earth to neutral voltage is sensed with a

voltage divider at the single-ended inputs, V1P and VM.

Figure 35 shows a block diagram of a 3-phase energy meter that

uses three ADE7912/ADE7913 devices and a microcontroller.

The neutral current is not monitored in this example. One 4.096

MHz crystal provides the clock to the ADE7912/ADE7913 that

senses the Phase A current and voltage. The

ADE7912/ADE7913 devices that sense the Phase B and Phase C

currents and voltages are clocked by a signal generated at the

CLKOUT/DREADY pin of the ADE7912/ADE7913 that is

placed to sense the Phase A current and voltage. As an alternative

configuration, the microcontroller can generate a 4.096 MHz

clock to all ADE7912/ADE7913 devices at the XTAL1 pin (see

Figure 36). Note that the XTAL1 pin can receive a clock with a

frequency within the 3.6 MHz to 4.21 MHz range, as specified

in Table 1.

The microcontroller uses the SPI port to communicate with the

ADE7912/ADE7913 devices. Three of its I/O pins, CS_A, CS_B,

and CS_C, are used to generate the SPI CS signals. The SCLK,

MOSI, and MISO pins of the microcontroller are directly

connected to the corresponding SCLK, MOSI, and MISO pins

of each ADE7912/ADE7913 device (see Figure 39). To simplify

Figure 35 to Figure 38, these connections are not shown.

Figure 35. 3-Phase Energy Meter Using Three ADE7912/ADE7913 Devices

NEUTRAL PHASE A

PHASE A

ADE7912/

ADE7913

GNDISO

V1P

VAN

NEUTRAL

EARTH

NEUTRAL LINE

ADE7912/

ADE7913

V1P

GNDISO

CS_A

CS_B

CS_C

SCLK

MOSI

MISO

I/O

MICROCONTROLLER

ISOLATION

BARRIER

PHASE A

ADE7912/ADE7913

PHASE B

ADE7912/ADE7913

PHASE C

ADE7912/ADE7913

V1P

V2P

GNDMCU

GNDISO_A

XTAL2

XTAL1

SCLK

MOSI

MISO

V1P

V2P

GNDMCU

GNDISO_B

XTAL2

XTAL1

SCLK

MOSI

MISO

V1P

V2P

GNDMCU

GNDISO_C

XTAL2

XTAL1

SCLK

MOSI

MISO

LOAD

4.096MHz

CRYSTAL

CLKOUT/

DREADY

CLKOUT/

DREADY

CLKOUT/

DREADY

ADE7913 数据表(PDF) 23 Page - Analog Devices

ADE7913 数据表(HTML) 23 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

数据表下载

链接网址

ADE7913 数据表(PDF) 23 Page - Analog Devices

ADE7913 数据表(HTML) 23 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

数据表 下载

链接网址

数据表下载