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EM773 Energy Metering IC

Technical Training

“The world’s first ARM with

smart metering metrology hardware!”

Energy Metering IC for Non-Billing Meters

EM773

Perfect solution for non-billing metering apps

– Plug meters

– SMART appliances

– Industrial & consumer sub-meters

Exceeds market requirements with better

than 1% metering accuracy

No metering know-how required

Product differentiation via application SW

Wireless M-Bus demonstrator design

Option for wired UART, SPI or I2C metrology

output to local system or LCD display

Energy Metering IC for Non-Billing Meters

EM773

Cortex-M0

48 MHz Up to 32 KB

Flash

Up to 8 KB

SRAM

1x UART

RS485 / IrDA

1x SPI

1x I2C

Advanced Peripheral Bus

Metrology

Engine

33-pin HVQFN

Built-in metrology engine

hardware and software

Application programmable

UART available for

communications port

Standard ARM support

ecosystem available for

easy development

Optimized metrology inside with optional network connection

EM773 Metrology Engine Inputs

Energy Metering IC EM773

Principle block diagram

Power supply

–3.3V as V

DD required

Analog circuitry for

current measurement

– accuracy options

Analog circuitry for

voltage measurement

Oscillator

Power in

Load

Opamp

Metrology Processor

core

Serial

interfaces

Memory

Energy IC

Rshunt

Vreg

Vcc

Power Supply

Clock

engine

I2C

Power meter

Data output

AC to DC

Power in

Load

Opamp

Metrology Processor

core

Serial

interfaces

Memory

Energy IC

Rshunt

Vreg

Vcc

Power Supply

Clock

engine

I2C

Power meter

Data output

AC to DC

Energy Metering IC EM773

Key components of BOM

Power in

Load

Opamp

Metrology Processor

core

Serial

interfaces

Memory

Energy IC

Rshunt

Vreg

Vcc

Power Supply

Clock

engine

I2C

Power meter

Data output

AC to DC

Power in

Load

Opamp

Metrology Processor

core

Serial

interfaces

Memory

Energy IC

Rshunt

Vreg

Vcc

Power Supply

Clock

engine

I2C

Power meter

Data output

AC to DC

Circuitry Device Type Quantity Remark

Power Supply

(not needed if regulated AC to DC SMPS 1 TEA1520T

3.3V VDD is available) Voltage Reguilator 1 SA57000-33D

C urrent Meas urement

(2 current ranges) Shunt Resistor 1

Operational Amplifier 2 NE5234

(4 inside single IC)

Voltage Measurement

Resistor Divider 2

Operational Amplifier 1 NE5234

(4 inside single IC)

Oscillator

Crystal 1 12 MHz

Energy Metering IC EM773: Circuit Example

Wireless Plugmeter

POWER

MEASURE

WIRELESS

OL2381

EM773

Energy Metering IC EM773: Circuit Example

Wireless Plugmeter

POWER

MEASURE

WIRELESS

OL2381

EM773

OPTIONAL

Energy Metering IC EM773: Layout Example

Wireless Plugmeter

Voltage measurement circuit

Voltage Divider

– Cost efficient solution

Transformer

– Full galvanic isolation

Current measurement circuit

Shunt Resistor

– Series resistor with defined low

resistance

– Cost efficient solution

Current Transformer

– Low dissipation at high current

– Standalone or PCB mounted

EM773 Analog Input Circuit Options

Energy Metering IC EM773

Definition of API calibration input values

API Input: Voltage and Current

– Start Metrology Engine with standard settings for Vpp, I1pp and I2pp derived

from input circuits

– Measure voltage and current from a calibrated source

– Correct the voltage and current ranges Vpp, I1pp and I2pp with the relative

difference

API Input: Phase Correction

– Measure the phase difference between voltage and current channels for two

resistive loads (high current and low current) and enter this value Phi1 and

Phi2 as the required phase correction

Energy Metering IC EM773

Calibration

Real time calibration adjustments

– The calibration parameters can be adjusted real-time by the application

running on the Cortex M0 processor core.

– This feature can for example be used to implement temperature

compensation or to switch between different measurement inputs

EM773 Calibration API

17.4.1 Metrology ranges

The following structure is used to configure the voltage range, current ranges and

the phase corrections for the I_HIGHGAIN and I_LOWGAIN gain current

channels:

typedef struct metrology_ranges_tag

{

float Vpp;

float I1pp;

float I2pp;

float DeltaPhi1;

float DeltaPhi2;

} metrology_ranges_t;

EM773 Measurement Output API

typedef struct metrology_result_tag

{

float V;

float I;

float P;

float Q1;

float S;

float S1;

float PF;

float PF1;

float SN;

float N;

float THDI;

} metrology_result_t;

EM773 Calling Metrology Engine Driver (1/3)

1. Initialize metrology engine:

metrology_init(12000000, 50);

2. Set ranges for the metrology engine:

metrology_ranges_t metrology_ranges;

metrology_ranges.Vpp = (float)954.67;

metrology_ranges.I1pp = (float)2.84;

metrology_ranges.I2pp = (float)45.60;

metrology_ranges.DeltaPhi1 = (float)0.0;

metrology_ranges.DeltaPhi2 = (float)0.0;

metrology_set_ranges(&metrology_ranges);

3. Start the metrology engine:

metrology_start();

EM773 Calling Metrology Engine Driver (2/3)

4. Read the measured data:

while (running)

{

if (metrology_get_gainchannel() == CURRENT_CHANNEL1)

{

LED_ON(); /* signal measuring from I_HIGHGAIN */

}

else

{

LED_OFF();/* signal measuring from I_LOWGAIN */

}

if (metrology_read_data(&meter_result))

{

print_result(&meter_result);

}

ms_sleep(250);

}

EM773 Calling Metrology Engine Driver (3/3)

5. Stop the metrology engine:

metrology_stop();

EM773 Measurement Accuracy

RMS Voltage V 0.5 %

RMS Current I 0.5 % 1

Active Power P 1.0 % 1,2

Apparent Power S 1.0 % 1

Non-active Power N 2.0 % 1

Power Factor PF 2.0 % 1

Fundamental Reactive

Power Q1 2.0 % 1,3

Fundamental Apparent

Power S1 3.0 % 1

Fundamental Power

Factor PF1 4.0 % 1

Non-fundamental Apparent

Power SN 4.0 % 1

Current Total Harmonic

Distortion THDI 5.0 % 1,4

1For Ippmax/400 < Ipp < Ippmax

2Crosstalk in P from Q1 < 0.1% of Q1

3Crosstalk in Q1 from P < 0.1 % of P

4For THDV < 5 % and THDI > 40 %

Electricity Measurement Algorithms

Output for sinusoidal and non-sinusoidal voltage and current







kT dtv



1. RMS Voltage (V)

Electricity Measurement Algorithms

Output for sinusoidal and non-sinusoidal voltage and current

2. RMS Current (I)







kT dti



Electricity Measurement Algorithms

Output for sinusoidal and non-sinusoidal voltage and current

3. Active Power (P)







vidt



Electricity Measurement Algorithms

Output for sinusoidal and non-sinusoidal voltage and current

4. Apparent power (S)

5. Non-active power (N)

6. Power factor (PF)

VIS 

22 PSN 

PF 

Electricity Measurement Algorithms

Additional output for sinusoidal voltage

Fundamental Active Power (P1)

P1 = P

(sinusoidal voltage)







vidt



Electricity Measurement Algorithms

Additional output for sinusoidal voltage

7. Fundamental Reactive Power (Q1)

8. Fundamental apparent power (S1)

9. Fundamental power factor (PF1)

10. Non-fundamental apparent power (SN)

11. Current total harmonic distortion (THDI)

11 QPS 

PF 

2SSSN

THD N

I











kT dtdtvi





111

Electricity Measurement Algorithms

Energy calculations on EM773 CPU Core

12. Consumed Energy (T+)

13. Produced Energy (T-)

14. Total Energy (T)



 M

nPeriodCalculatio ncalculatio

TPT 1



 M

nPeriodCalculatio ncalculatio

TPT 1



M

nPeriodCalculatio ncalculatio

TPT 1

EM773 Development Tools

EM773 Tool Highlights

EM773 Starter Kit including:

– Plug meter with EM773 and OL2381

– USB transceiver with LPC1343 and OL2381

EM773 FREE software examples

– Downloadable from

http://www.NXP.com/smartmetering

IDEs Supporting EM773 Metrology Engine

– IAR Embedded Workbench for ARM (NOW!!!)

– Keil and Code Red (Coming soon!)

SWD debuggers

– All debuggers supporting Cortex-M0

PC Energy Display

M-Bus USB Adapter

EM773 Plug Meter

EM773 Online Community

NXP Smart Metering

http://www.nxp.com/smartmetering

EM773 Software Examples and Application Notes

http://ics.nxp.com/support/design/microcontrollers/smart.metering/

EM773 Online Support Forum

http://knowledgebase.nxp.com/

EM773 FREE Software Examples in More Detail

FREE Software consists of 3 components

1. EM773 project for plug meter examples

2. LPC1343 project for USB wireless transceiver

3. PC based application reading from USB receiver

Wireless M-Bus PC Energy Display

M-Bus USB Adapter

Plug meters

EM773 FREE Software Examples in More Detail

1. EM773 project for plug meter examples

Software Includes:

►Metrology engine supported with closed source firmware driver

►Open source ARM M0 application using metrology engine API

►Open source wireless M-Bus for transmitting power data

►Open source UART and I2C wired metrology output options

Software Example Dependencies:

►IAR Embedded Workbench 5.50+ (Keil and Code Red in roadmap)

►FreeRTOS (Metrology Engine can be used independently)

Application Ideas

Other communication options possible such as PLC, Zigbee

Local UART, I2C, SPI serial ports for data output and control

ARM Cortex M0 may be used for data encryption (AES, 3DES, etc)

Wireless Plug Meter Product Specifications

16 AMaximum Current

Better than 0.5%*Voltage Accuracy

Better than 0.5%*Current Accuracy

Better than 1.0%*Active Power Accuracy

< 0.45 WPower consumption

400:1Dynamic Range

10 mWRF output power

50 or 60 HzNet Frequency

Up to 300 meters line of sightWireless range

Voltage Range 90 – 270 V

* Based on dynamic range of 400:1

EM773 FREE Software Examples in More Detail

2. LPC1343 project for USB wireless transceiver

Software Includes:

►Open source ARM M3 application using USB device driver

►Open source wireless M-Bus for receiving power data from up to 50

plug meters simultaneously (can be configured for more)

►All software included is open source c code

Software Example Dependencies:

►IAR Embedded Workbench 5.50+ (Keil and Code Red in roadmap)

►FreeRTOS (USB and M-Bus can be used independently)

Application Ideas

Bi-directional communication for sending commands to meters

Web based application bridge for metrology data

EM773 FREE Software Examples in More Detail

3. PC based application reading from USB receiver

Software Includes:

►Open source PC application using USB device driver

Software Example Dependencies:

►Microsoft Windows XP, Vista or Windows 7

►Microsoft .NET 4.0 or newer

Application Ideas

Improved graphical user interface (GUI) options

Web server for remote data access

Data logging and storage

List of ideas can go on and on…

Get Started Today!!!

1. Order an Energy Metering IC starter kit

2. Download FREE software examples and application notes

3. Run the demo application with a variety of different loads

4. Connect your debugger and IDE for software development

5. Use pin holes on the plug meter to evaluate custom

components with the EM773

6. Design your own EM773 prototype and product