Analog Devices EVAL-ADE7903EBZ Manuale utente

EVAL-ADE7903EBZ User Guide

UG-797

One Technology Way •P. O. Box 9106 •Norwood, MA 02062-9106, U.S.A. •Tel: 781.329.4700 •Fax: 781.461.3113 •www.analog.com

Evaluating the ADE7903 Σ-Δ ADC

FEATURES

Full featured evaluation board for ADE7903

PC control in conjunction with the EVAL-SDP-CB1Z

system demonstration platform (SDP-B)

PC software for control and data analysis (time and

frequency domain)

Standalone capability

EVALUATION KIT CONTENTS

EVAL-ADE7903EBZ evaluation board

ADDITIONAL EQUIPMENT NEEDED

EVAL-SDP-CB1Z (order separately), includes a USB cable

1 current sensing shunt

Precision current and voltage signal source

Minigrabbers

PC running Windows XP SP2, Windows Vista, or Windows 7

with USB 2.0 port

ONLINE RESOURCES

Documents

ADE7903 data sheet

EVAL-ADE7903EBZ user guide

Required Software

ADE7903 evaluation software (download from

product page)

Design and Integration Files

Schematics, layout files, bill of materials

GENERAL DESCRIPTION

The E VA L -ADE7903EBZ evaluation kit includes the evaluation

board, which along with the EVA L -SDP-CB1Z SDP-B board,

allows users to evaluate the performance of the ADE7903 Σ-Δ

ADC in a context very close to an actual single-phase meter

implementation. There is an isolated version of the ADE7903

Σ-Δ ADC available, the ADE7913; to evaluate the isolated

Σ-Δ ADC, use the ADE7913 evaluation kit (order separately

from Analog Devices, Inc.). Evaluation software written in

LabVIEW® provides access to the registers of the ADE7903

using a PC interface.

Full specifications on the ADE7903 are available in the product

data sheet, which should be consulted in conjunction with this

user guide when using this evaluation board.

TYPICAL SETUP

Figure 1. Evaluation Board Connected to the SDP Interface and SDP Boards

PLEASE SEE THE LAST PAGE FOR AN IMPORTANT

WARNING AND LEGAL TERMS AND CONDITIONS.Rev. 0 | Page 1 of 12

UG-797 EVAL-ADE7903EBZ User Guide

TABLE OF CONTENTS

Features .............................................................................................. 1

Evaluation Kit Contents................................................................... 1

Additional Equipment Needed....................................................... 1

Online Resources.............................................................................. 1

General Description ......................................................................... 1

Typical Setup ..................................................................................... 1

Revision History ............................................................................... 2

Evaluation Board Hardware ............................................................ 3

Overview........................................................................................ 3

Powering Up the Evaluation Kit Boards.................................... 4

Analog Inputs................................................................................ 4

Setting Up the Evaluation Board as an Energy Meter ............. 6

Evaluation Board Software...............................................................7

Installing the Drivers ....................................................................7

Installing and Uninstalling the ADE7903 Evaluation

Software ..........................................................................................7

Main Window ................................................................................8

Evaluation Software Functions........................................................9

Start ADE7903 ...............................................................................9

Waveform Sampling................................................................... 10

Temperature Measurement....................................................... 11

Read and Write Registers .......................................................... 11

Reset the ADE7903 .................................................................... 11

REVISION HISTORY

12/14—Revision 0: Initial Version

Rev. 0 | Page 2 of 12

EVAL-ADE7903EBZ User Guide UG-797

Rev. 0 | Page 3 of 12

EVALUATION BOARD HARDWARE

OVERVIEW

To evaluate t he ADE7903, connect the evaluation board and the

SDP-B board together (see Figure 1). The EVAL-ADE7903EBZ

evaluation board, which is populated with one ADE7903 ADC,

can be used for evaluation of the standalone ADC or as a possible

single-phase meter implementation example (see Figure 3).

The EVAL-ADE7903EBZ evaluation board is connected to the

EVAL-SDP-CB1Z SDP-B Blackfin® board using the 120-pin

connector. Be sure to order EVAL-SDP-CB1Z when ordering

the EVAL-ADE7903EBZ evaluation kit; the evaluation kit and

the SDP-B board are purchased and packaged separately, but

must be used together.

The SDP-B board consists of a Blackfin ADSP-BF527 micro-

controller that handles all the communications from the PC

to the ADE7903 device populating the evaluation board (see

Figure 2).

Figure 2. Evaluation Kit Connection Diagram

Figure 3. EVAL-ADE7903EBZ Evaluation Board

ADE7903 EVALUATION BOARD

IP_INIM_INGNDV1P_INV2P_IN

ADE7903

FILTER

NETWORK

POWER AND DATA ISOLATION

SDP INTERFACE

CIRCUITRY

USB

CONN

SDP BLACKFIN BOARD

12927-003

12927-002

UG-797 EVAL-ADE7903EBZ User Guide

POWERING UP THE EVALUATION KIT BOARDS

The interface board receives power via the USB cable connected

to the PC. A 3.3 V regulator then powers the SDP-B board

microcontroller and, across the isolation barrier, the ADE7903

ADC populating the evaluation board. No additional power

source is required for the ADE7903 evaluation kit boards.

ANALOG INPUTS

Current and voltage signals are connected at the test pins placed

on the evaluation board. All analog input signals are filtered

using the on-board antialiasing filters before the signals are

connected to the ADE7903 ADC. The components used on the

board are the values recommended for use with the ADE7903.

Current Sense Inputs (IP_IN and IM_IN Test Pins)

The ADE7903 measures the voltage across a shunt at its IP and

IM pins. Figure 4 shows the structure used for the current

input.

Figure 4. Current Input Structure on the Evaluation Board

R8, R9, R20, and R21 are 0 Ω resistors that do not need to be

implemented on a real meter board. R15/C12 and R16/C15

RC networks are the antialiasing filters. The default corner

frequency of these low-pass filters is 4.8 kHz (1 kΩ/33 nF).

These filters can easily be adjusted by replacing the components

on the evaluation board.

The E1, E2, and E3 ferrite beads filter the high frequency noise

that may be induced into the wires.

The absolute maximum voltage on the IP and IM pins of the

ADE7903 is ±2 V. The D3 and D6 diodes protect the IP and IM

pins against voltages greater than ±1 V. The maximum signal level

permissible at the IP pin of the ADE7903 is ±0.03125 V peak.

The signal range must not exceed ±0.03125 V, with respect to

AGND_ADC, for specified operation.

The shunt is connected between the IP_IN and IM_IN test pins.

The shunt maximum value is a function of the maximum

current to be measured on every phase:

1025.31

−

where:

1025.31 3−

is the rms value of the full-scale voltage accepted at the ADC input.

IFS is the maximum current to be measured. It is called the full-

scale current.

Figure 5 shows how a shunt is connected to the current input

structure. The shunt is connected between the P1 and P1’

energy meter line inputs. The IP_IN and IM_IN test pins are

connected to the shunt measurement poles, while GND, the test

pin that is the ground of the ADE7903, is connected to the

ground pole of the shunt.

Figure 5. Example of a Shunt Connection

IM_IN

IP_IN

GND AGND_ADC

ADE7903

0Ω R15

1kΩ

0Ω R16

1kΩ

R20

0Ω

R21

0Ω

C12

33nF

C15

33nF

D3 D6

12927-004

IM_IN

IP_IN

GND AGND_ADC

ADE7903

0Ω R15

1kΩ

0Ω R16

1kΩ

R20

0Ω

R21

0Ω

C12

33nF

C15

33nF

D3 D6

TO P1'

METER

INPUT

TO P1

METER

INPUT

12927-005

Rev. 0 | Page 4 of 12

EVAL-ADE7903EBZ User Guide UG-797

Phase Voltage Sense Inputs (V1P_ IN Test Pin)

The phase-to-neutral voltage input connections on the E VA L -

ADE7903EBZ evaluation board can be directly connected to the

line voltage source between the GND and V1P_IN test points for

phase-to-neutral voltage. These voltages are attenuated using a

simple resistor divider network before they are supplied to the

ADE7903. The attenuation network on the voltage channels is

designed so that the corner frequency (3 dB frequency) of the

network matches that of the antialiasing filters in the current

channel inputs. This design prevents the occurrence of large

energy errors at low power factors.

The V1P_IN path in Figure 6 shows a typical connection of the

voltage inputs; the resistor divider consists of three 330 kΩ

resistors (R1, R5, and R10) and one 1 kΩ resistor (R14). The

antialiasing filter R14/C11 matches the R12/C9 filter in the VM

path. The absolute maximum voltages on the V1P and VM pins

of the ADE7903 are ±2 V. T h e D 1 , D7, D4, and D9 diodes

protect the V1P and VM pins against voltages greater than ±2 V.

The maximum signal level permissible at the V1P pin of the

ADE7903 is ±0.5 V peak. The signal range must not exceed

±0.5 V with respect to GND for specified operation.

The E4 and E5 ferrite beads filter the high frequency noise that

may be induced into the wires.

Auxiliary Voltage Sense Inputs (V2P_IN Test Pin)

The auxiliary voltage input connections on the EVA L -

ADE7903EBZ evaluation board can be directly connected to

the line voltage sources between V2P_IN and GND for the

auxiliary voltage.

The V2P_IN path in Figure 6 shows a typical connection of the

Phase A auxiliary voltage input. It is very similar to the V1P_IN

path explained in Phase Voltage Sense Inputs (V1P_ IN Test Pin)

section.

Figure 6. Phase Voltage Input Structure on the Evaluation Board

VDD and Ground Pin Management

The ADE7903 package has four ground pins (GND): Pin 2,

Pin 10, Pin 11, and Pin 20. Figure 7 presents their management,

on the side of the current and voltage inputs, in the case of an

ADE7903. It is important to note that Pin 11 (GND) must be

connected to either Pin 2 or Pin 10 (GND) outside the package.

Similarly, Pin 19 (VDD) must be connected directly to Pin 1

(VDD) in the shortest path outside of the package because they

are not internally connected. The C1A, C2A, and C4A

decoupling capacitors on the VDD pins are connected to the

closest ground pin. The decoupling capacitors, C5A and C6A

on the analog LDO pin and C13A and C14A on the voltage

reference pin, must be separate from the VDD circuitry and are

connected to ground (Pin 10).

Figure 7. Isolated Ground Pins Management

The P1 meter input constitutes the AGND_ADC1 signal (see

also Figure 5). AGND_ADC1 is then connected to GND

(AGND_ADC signal) through a ferrite bead (E2).

V1P

AGND_ADC

V2P

V1P_IN

V2P_IN

TP14

TP15

ADE7903

330kΩ R5

330kΩ R10

330kΩ

R12

1kΩ

330kΩ R6

330kΩ R11

330kΩ

R14

1kΩ

C11

33nF

R13

1kΩ C10

33nF

D9D7

D10D8

12927-006

PHASE

ADE7903

VDD

GND

LDO

VREF

TP11

GROUND

CONNECTION

BETWEEN PIN 2

AND PIN 10

INTERNAL TO

ADE7903

C4A

C1A

C5A C6A

C13A C14A

AGND_ADC

AGND_ADC1

PIN 19

VDD

C2A

GND

12927-007

Rev. 0 | Page 5 of 12

UG-797 EVAL-ADE7903EBZ User Guide

Rev. 0 | Page 6 of 12

SETTING UP THE EVALUATION BOARD AS AN

ENERGY METER

Figure 8 shows a typical setup for the EVAL-ADE7903EBZ

evaluation board. In this example, an energy meter for a 1-phase,

2-wire distribution system is shown. A shunt is used to sense

the phase current and is connected as depicted in Figure 8. The

line voltage is connected directly to the board, and the board is

supplied from one power supply provided by the PC through

the USB cable.

The ADE7903 can be used in conjunction with the

ADE7913/ADE7912 in a single-phase system to monitor both

the line and the neutral, if needed. In an alternative application

where isolation from the neutral line is not required, the

ADE7903 can be used on the neutral in a 3-phase distribution

system, along with three ADE7913/ADE7912 devices. The

isolated ADC allows isolation from the line, while the ADE7903

can be used on the neutral where isolation may not be required.

To evaluate t he ADE7913, refer to the ADE7913 product page.

Figure 8. Typical Setup for the EVAL-ADE7903EBZ Evaluation Board

for 1-Phase Distribution System

Using the Evaluation Board with Another Microcontroller

It is possible to manage the EVAL-ADE7903EBZ evaluation

board with a different microcontroller mounted on another

board. The evaluation board can be connected to this second

board through the P8 connector, shown in Figure 9. In this case,

the SDP-B Blackfin board is unused.

Figure 9. SDP Interface P8 Connector

IP_IN

IM_IN

NEUTRAL

LOAD

PHASE

GND

V1P_IN

ADE7903

EVALUATION

BOARD PINS

12927-008

12927-009

USB_VBUS

CLKOUT/DREADY_SDP

CS_SDP

MOSI_SDP

MISO_SDP

SCLK_SDP

SDA_SDP

SCL_SDP

EEPROM_A0

GND

FX8-120S-SV (21)

120

119

118

117

116

115

114

113

112

111

110

109

108

107

106

105

104

103

102

101

100

GND

FX8-120S-SV (21)

EVAL-ADE7903EBZ User Guide UG-797

Rev. 0 | Page 7 of 12

EVALUATION BOARD SOFTWARE

The EVAL-ADE7903EBZ evaluation board is supported by

Windows®-based software that allows the user to access all the

functionality of the ADE7903.

The software communicates with the SDP-B Blackfin board

using the USB. The microcontroller communicates with the

ADE7903 ADC on the evaluation board to process the requests

sent from the PC.

INSTALLING THE DRIVERS

When using the ADE7903 evaluation tools for the first time, a

driver must be installed to allow successful communication.

The driver SDPDriversNET.exe can be found in the evaluation

software package in the SDP drivers folder.

To install the driver, follow this procedure:

1. When the Setup Wizard appears, click Next, and follow the

installation instructions.

Figure 10. SDP Drivers Setup

2. When the installation is complete, click Finish to close the

window.

Connect the USB cable from the PC to the SDP-B Blackfin

board. Windows detects the device and locates the correct

driver automatically.

INSTALLING AND UNINSTALLING THE ADE7903

EVALUATION SOFTWARE

The ADE7903 evaluation software is supplied with the

evaluation software package. It contains the LabVIEW-based

program that runs on the PC. This program must be installed.

Before using the evaluation software on the PC for the first time,

run the installer. This installer is available in the installation_files

folder. If a copy of LabVIEW 2010 is available on the PC, the

executable is provided in the executable folder. The LabVIEW

source files are provided in the LabView_project\source folder.

1. To install the ADE7903 evaluation software, double-click

installation_files\setup.exe to launch the setup program

that automatically installs all the software components,

including the uninstall program, and creates the required

directories.

2. To launch t he s oftware, go to Start > Programs >

ADE7903 Evaluation Software and click ADE7903

Evaluation Software.

Both the ADE7903 evaluation software program and the NI

run-time engine can be uninstalled using the Add/Remove

Programs option in Control Panel.

1. Before installing a new version of the ADE7903 evaluation

software, first uninstall the previous version.

2. From the Windows Control Panel, click Add/Remove

Programs.

3. Select the program to uninstall and click Add/Remove.

12927-010

UG-797 EVAL-ADE7903EBZ User Guide

Rev. 0 | Page 8 of 12

MAIN WINDOW

When the software is launched, the main window opens. This

window contains two areas: the main menu on the left, and a

box that verifies that the PC is connected to the SDP-B board

on the right (see Figure 11).

The software automatically detects the SDP-B Blackfin board.

If the port detection is successful, the box on the right displays

Connected, as shown in Figure 11.

The Function menu, shown in Figure 12 at the top of the

window, appears in every window throughout the software.

With this menu, navigate from any main menu selection to

another main menu selection at any time.

Figure 11. Main Window of the ADE7903 Evaluation Software

Figure 12. Function Menu on Main Window

Troubleshooting the COM Port Detection

If the software does not detect the SDP-B Blackfin board, the

message shown in Figure 13 displays.

Figure 13. SDP-B Blackfin Board Not Detected Message

Wait approximately 40 seconds and click Rescan to retry

connecting to the SDP-B board. If a message stating 1 matching

system found does not appear, take the following steps:

1. Click Cancel and Exit out of the evaluation software.

2. Verif y that the ADE7903 board is connected to the SDP-B

Blackfin board and that the SDP-B Blackfin board is

connected to the PC using the USB cable.

3. Ensure that the required drivers are installed as described

in the Installing the Drivers section. Some drivers are

automatically installed during the first startup of the board.

Drivers only need to be installed once for a particular PC.

4. Using the Device Manager tool, ensure that the SDP-B

Blackfin board was recognized by the PC and appears

under the ADI Development Tools entry as Analog

Devices System Demonstration Platform SDP-B.

5. Launch the ADE7903 evaluation software again.

12927-011

12927-012

12927-013

EVAL-ADE7903EBZ User Guide UG-797

Rev. 0 | Page 9 of 12

EVALUATION SOFTWARE FUNCTIONS

The ADE7903 evaluation software allows access to all the

registers and features of the ADE7903. The main menu options

available are

Start the ADE7903

Waveform Sampling

Temperature Measurement

Read and Write Registers

Reset the ADE7903

Exit button (closes the software)

These options provide access to all internal registers and allow

evaluation of the ADC performance. To access these functions,

click the desired option in the main menu (see Figure 11).

Clicking an option in the main menu displays a window where

the specific function can be accessed. Each window includes a

Main Menu button used to return to the main window.

Note that only one option from the menu can be open at a time;

click Main Menu to return to the main window before choosing

another option from the menu.

START ADE7903

Figure 14 shows the Start ADE7903 window. The ADE7903 is

clocked from a 4.096 MHz crystal. The software automatically

starts the ADE7903 ADC with the following default settings:

The bandwidth of the digital low-pass filter of the ADC is

set at 3.3 kHz.

The ADC output frequency is set at 8 kHz.

The CLKOUT/DREADY pin is set to generate a DREADY

signal at the output frequency to signal when the data is

ready from the ADC.

The secondary voltage channel is set to read from the V2P

input rather than from the temperature sensor.

If different settings are desired, select them from the boxes in

the right half of the window. Click Configure to update the

ADE7903.

Figure 14. Start ADE7903 Window

The CONFIG register box shows the current value of the

CONFIG register, and can be used to verify the changes made

to the ADE7903.

The Lock Registers button can be used to protect the

configuration registers in the ADE7903. This button writes

directly to the lock register (0xA). When the registers are

protected, the boxes on the right are greyed and the Lock

Registers light turns on. Note that when the registers are

protected, no register can be further written until the protection

is disabled. It is therefore recommended to evaluate the

ADE7903 ADC while keeping the registers protection disabled.

Click Read to read the current configuration. Click Configure

to write the new settings. Click Reset to reset the ADE7903.

Click Main Menu to close this window and open the main

window.

12927-014

UG-797 EVAL-ADE7903EBZ User Guide

Rev. 0 | Page 10 of 12

WAVEFORM SAMPLING

Figure 15 shows the Waveform Sampling window. This

window provides full access to the ADC outputs (waveforms) of

the ADE7903 ADC on the board. To display waveforms, follow

these steps:

1. Enter an acquisition time in the Accumulation Time (ms)

box, expressed in milliseconds.

2. Select the Channels of the ADE7903 to be visualized by

checking any combination of the Current, Volt age1, and

Voltage2 boxes. The color of each waveform can be changed

as desired by clicking the color next to the check box.

3. Click Capture to display the waveforms on the plot. After

the data is captured, the check boxes under Channels can

be modified to display any combination of waveforms from

that data capture.

The SDP-B Blackfin board acquires the waveform samples

using the ADE7903 DREADY signal as an interrupt. The blue

bar above the plot shows the acquisition progress.

To save the waveforms to a file,

1. Click the folder icon below Save File To to select the folder

for the file to be saved.

2. Click Save As .txt to save the waveform data to a file.

The program stores every waveform into a file named

ADE7903_WAVEFORM_xxxx.txt, where xxxx is a number

starting at 0000 and incremented by 1 to keep from overwriting

a past waveform file. The file includes the raw data with the

columns being time, current channel, Voltage Channel 1, and

Voltage Channel 2. The file is semicolon (;) delimited and can

easily be imported into a spreadsheet.

To shift and zoom in on the plot, use the buttons in the bottom

left-hand corner of the plot area.

To enable a Fourier analysis of the acquired waveforms, change

the position of the Select Analysis switch from Waveforms to

FFT. In this case, the window shown in Figure 16 is enabled.

Only one waveform at a time is visualized in this plot; select the

Channels boxes accordingly.

Select the type of windowing from the Window drop-down

menu: Hanning, Blackman-Harris, or none.

Various FFT Settings can be selected: 0 dB level reference may

be at the signal peak, the theoretical maximum, or at a manual

entry. When selecting Signal Peak, the plot uses the amplitude

of the maximum peak of the waveform as the 0 dB level and

writes it in the Manual entry box.

Other selections include the Bandwidth under analysis (default

is between 10 Hz and 4000 Hz), the Fundamental Frequency

(the default is 50 Hz), the width of the signals extracted for SNR

analysis, Fund/Harm Sideband Bins (the default is 10 Hz), and

the Number of Harmonics used in the ADC specifications

visualized under the plot (default is 6).

When the FFT plot is visualized, the program calculates and

visualizes the following ADC specifications:

SNR (signal-to-noise ratio)

THD (total harmonic distortion)

SINAD (signal-to-noise-and-distortion ratio)

SFDR (spurious-free dynamic range)

Signal (rms of the fundamental component)

Noise (rms of the noise)

Harmonics (rms value of all harmonics)

Figure 15. Waveform Sampling

Figure 16. Fourier Analysis

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