200403 PMeter for Training
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Transcript of 200403 PMeter for Training
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Electronic Energy Meter
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ContentsContents
BackgroundClassificationPrinciple
Block diagramFeature of the solutionHardware configure
How to reuse the solutionOther devices
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BackgroundBackground
Induction meterLack of electric powerImprove the management of electric powerusage
Electric technology development (A/D, MCU,DSP)
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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
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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
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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.
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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
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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
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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.
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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
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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
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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
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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
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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.
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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
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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.
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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
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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
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ST7538ST7538
ST7538 Main Features Receiver Sensitivity 1mVrms Maximum Input Signal 2.5Vrms Operating Current
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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)
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PlanPlan
Make 10 sets demo board of multi-rate before week12
Three phase multi functional power meter