200403 pmeter for training

8/6/2019 200403 PMeter for Training

1/21

http://www.stmcu.com1

Electronic Energy Meter


2/21


ContentsContents

BackgroundClassificationPrinciple

Block diagramFeature of the solutionHardware configure

How to reuse the solutionOther devices


3/21


BackgroundBackground

Induction meterLack of electric powerImprove the management of electric powerusage

Electric technology development (A/D, MCU,DSP)


4/21


ClassificationClassification

According to measurement energy accuracy class 0.2s, 0.5, 0.5s, 1.0 and 2.0 According to work principle of measurement unit

Static (solid) type meter

Induction (mechanical ) meter

According to connection method Single phase meter

3 phase/3 wire meter

3 phase/4 wire meter

According to functionPulse meter

Multi-rate meterPrepayment meter

Power line meter

Multi-function meter


5/21


Current and voltage of electricity are sampled in the same time.

Concepts of Electronics MeteringConcepts of Electronics Metering

The immediate powerconsumption is

calculated.

Accumulatedenergy usage isdisplayed with stepcounter for userreference.

CurrentSampling

Voltage

Sampling

Pulse

output

+

-

ADC

DIGITAL TO FREQUENCE

CONVERTER

*

11011001

110101

PHASE

CORRECTION

MULTIPLIER

HPF LPF

DGND

CLKIN CLKOUT SCF S0 S1 REVP CF F1 F2

RESET

SIGNALPROCESSING

BLOCK

DVDDAC/DCAGNDAVDDG1G0

PGA

x1,x4,x8,16

V1P

V1N

POWER SUPPLY

MONITOR

AD7755

2.5VREFERENCE

REFIN/OUT

4K;

V2P

V2N

+

-

ADC

An example of measuring device


6/21


Advantage of Electronics MeteringAdvantage of Electronics Metering

Save natural material Higher reliability and accuracy Software automatic calibration available Prepayment available Multi-rate charging Remote meter reading Energy usage statistic Anti-tampering Multiple information display

Same concept applies to gas and water metering.


7/21


P

N

Voltage

sensor

Current

sensor

ADCADC

LCD Display

LCD Driver

Signal

processing

Application

ManagememtRTC

Reset Circuit,

Real Time Clock,

Battery

Power Supply

Smart Card

Reader

AMR

CommunicationSignal Processing

+

+

Features summary:KWH measures

LCDDisplay

Storage Calibration Data

AntiTampering

Maximum demand

with date and time Date&Time

Cumulative Energy

Automatic meter reading(IR, RF, IrDA, PLM)

Multi Tariff (Peak hours,normal hours, etc)

Metercalibration troughsoftware

Pre-paid module ( Cardtypes used: EEPROM card,Security card, Smart card)

Low

End

MediumEnd

High

End

RAM

FLASH or

ROM

EEPROM

Features and General Block DiagramFeatures and General Block Diagram

LED Driver


8/21


Benefit of ST solutionBenefit of ST solution

Short learning curve

Wide routines library available

Existing know-how can be kept

Wide selections of configuration

Pushs back the hardware limitationsPossible evolution to higher speed

Take full advantages of C language

Enhanced features

Blocked Architecture

Low risk

Quality guaranteed

Reduced time to market

Industrial proved

solution


9/21


Full set solution from STFull set solution from ST

LED

LCD DIPLAY

Sensor

Real timeclock

Crystal

Battery

M41T81

ADC

SIGNAL

PROCESSING

STPM01 or

AD775x

Application

Managment

FLASH or

ROM

RAMLCD DriverBy ST software

ST72324

EEPROM

24Cxx

Communication

Front-End

Communication

signal processing

ST7538

RS485

Infrared

ICP

POWER

SUPPLY

Break news: STPM01 sample is

available by this April and ship by

next January.


10/21


Feature of the solutionFeature of the solution

Precise measurementMeasure and record on active accumulative energy

Measure individual active accumulative energy for positive and negativedirection

Measure individual active accumulative energy for different tariff rates(peak, day, low)

Record and save all kind of the forward energy for 12 months

Clock, interval time and tariff-rateThree tariff rate (Peak, Day, Low) and 12 interval times

Hardware clock device with high accurate date and time, and withoutleap year problem.

Software compensation to ensure the higher accuracy.

Accuracy is better than 0.5S/Day


11/21


Feature of the solutionFeature of the solution

Display: to show user the different kinds of energy usage in LCDSoftware driver with I/O pins driving LCD panel directlyThere are 15 items to be displayed in turn. The display item can be hided or showed

via communication programming. The display duration for every item can be set from

1s to 10s.

There are two LEDs to indicate the different tariff rate.

Communication: to implement the Automatic Meter Reading (AMR) andremote configurationCompliant with the protocol of JiangSu Province

Electronic-optical isolated RS485 interface

Infrared interface

PLM interface

Capability of remote configuration with accessing date/time recorded

Storage: to save the energy usage in a non-volatile memoryAfter power cut, all the data in Eeprom are valid over 10 years

Write/read data with verification


12/21


Advantages of solutionAdvantages of solution

Software LCD driver with I/Opins drive LCD directly.

Internal A/D channel to monitorthe power failure and the batteryusage directly.

The infrared carrier 38kHz isgenerated and modulated the data by MCU directly.

With internal watch dog Adjusting the accuracy of clock via software method

ESD protection in all Pins High sink pinsto drive LED directly IAP-- In-Application Programming, ICP-- In Circuit programming


13/21


Hardware configurationHardware configuration

SCI for RS485 communication 1 timer for Infrared communication

1 timer for PWM(38kHz) Basic time for LCD refresh

1 interrupt I/O pin for infrared communication

2 A/D channels for detecting power failure and battery usage High sink pinsto drive LED indicator directly


14/21


How to use the solutionHow to use the solution

The solution consists of 6 files: main.c comm

.c interface

.c eeprom

.crtc.c init.c energy.c i2c.c.

Modify the I/O pin function: define.h and Initio(); comm.c for adding or deleting the communication command Interface.c for driving the LCD and tariff rate indication

Eeprom.c for how to organize the data to be read/written from/ineeprom Rtc.c for reading and writing real time clock Init.c for the initiallization Energy.c for energy pulse measure and energy calculation I2c.c: to read and write data from/in eeprom Main.c for program loop With this detailed partition, user may focus on the

parts that they want to add/modify and so on.


15/21


Main devices in solutionMain devices in solution

Model Provider note

MCU ST72F324 ST

EEPROM 24C16W ST

PLM ST7538 ST

RS485 ST485E ST

RTC M41T81 ST

Switch power Viper12 ST

Regulate ST7805 ST

Measure unit ADE7755 AD STPM001 by ST


16/21


Other MCUOther MCU

STLite0X: it is suitable for pulse power meter STLite2X: suitable to implement power meter without display,

for example: shanghai protocol.

ST72F324K: suitable to implement multi-rate/prepay powermeter with display, but It is no way to drive display panel,because of lack of I/O pins. It need other driver to drive LCD orLed display.

ST72F324J: suitable to implement multi-rate/prepay powermeter with display, and it can drive LCD or LED directly.


17/21


Other devicesOther devices

ST485EBLOW QUIESCENT CURRENT: 300QA

-7V TO 12V COMMON MODE INPUT VOLTAGE RANGE

DRIVER MAINTAINS HIGH IMPEDANCE IN 3-STATE OR WITH THE POWER OFF

70mV TYPICAL INPUT HYSTERESIS

30ns PROPAGATION DELAYS, 5ns SKEW

OPERATE FROM A SINGLE 5V SUPPLY

CURRENT LIMITING AND THERMAL

SHUTDOWN FOR DRIVER OVERLOAD PROTECTION

ESD PROTECTION: s15KV (H.B.M.) s8KV (IEC-1000-4-2 CONTACT DISCHARGE)

ALLOWS UP TO 256 TRANSCEIVERS ON THE BUS


18/21


M41T81M41T812.0 TO 5.5V CLOCK OPERATING VOLTAGE

COUNTERS FOR TENTHS/HUNDREDTHS OF SECONDS, SECONDS,MINUTES,HOURS, DAY, DATE, MONTH, YEAR, and CENTURY

SERIAL INTERFACE SUPPORTS I2C BUS (400KHz PROTOCOL)

WATCHDOG TIMER

BATTERY BACK-UPOPERATING TEMPERATURE OF 40 TO 85rC

PACKAGE OPTIONS INCLUDE A 28-LEAD EMBEDDED CRYSTALSOIC

AUTOMATIC SWITCH-OVER and DESELECT CIRCUITRY

PROGRAMMABLE ALARM and INTERRUPT FUNCTION (valid even

during Battery Back-up Mode)LOW OPERATING CURRENT OF 400A

ULTRA-LOW BATTERY SUPPLY CURRENT OF 1uA


19/21


ST7538ST7538

ST7538 Main Features Receiver Sensitivity 1mVrms Maximum Input Signal 2.5Vrms Operating Current


20/21


Cost EvaluationCost Evaluation

Chip set: 35.0 (ST72F324, 24WC12, RS485, M41T81,ADE7755)

Battery: 15.0LCD panel: 6.0Capacitor: 10 x 0.01 = 1.0Resistance: 100 x 0.02 = 2.0PCB: 6.0

Transformer: 5.0Plastic box: 12.0Others: 10.0 (electrolytic capacitor, diode, and so on)


21/21


PlanPlan

Make 10 sets demo board of multi-rate before week12

Three phase multi functional power meter

200403 pmeter for training

Documents