a 9.0

PRACTICAL DESIGN TECHNIQUES FORSENSOR SIGNAL CONDITIONING

1 Introduction

2 Bridge Circuits

3 Amplifiers for Signal Conditioning

4 Strain, Force, Pressure, and Flow Measurements

5 High Impedance Sensors

6 Position and Motion Sensors

7 Temperature Sensors

8 ADCs for Signal Conditioning

n 9 Smart Sensors

10 Hardware Design Techniques

a 9.1

CONTROLLING A REMOTE ACTUATORUSING A 4-20mA LOOP

4-20mADAC

µCHOST

COMPUTER

REGULATOR

LOOPSUPPLY

RSENSE

CONTROL ROOM

4-20mA OUTPUT

ACTUATOR

AD420

12V TO 32V

LOOPRETURN

a 9.2

4-20mA LOOP POWERED SMART SENSORS

EN

SO

R

ADC µC4-20mA

DAC

RSENSE

AD421

ICOMMON < 4.00mA

ADC µCHOST

COMPUTER

REGULATORLOOP

SUPPLY

RSENSE

3.3V / 5V

AD7714/AD7715

IAD421 < 0.75mA

CONTROL ROOMDMOS FET

DMOS FET: Supertex DN2535 Siliconix ND2020L or ND2410L

4-20mA RETURN

LOOPPOWER

I µC+SENSOR < 2.75mA

I AD7714/AD7715 < 0.50mA

ICOMMON

a 9.3

HART INTELLIGENT REMOTE TRANSMITTERUSING AD421 LOOP-POWERED 4-20mA DAC

SE

NS

OR

ADC µC4-20mA

DACAD421

HARTMODEM

BELL 202

WAVEFORMSHAPER

BANDPASSFILTER

LOOP POWER

LOOP RETURN

CC

HT20C12 / 20C15 (Symbios Logic)

HART DIGITAL SIGNAL: 1200Hz, 2200Hz FREQUENCY SHIFT KEYING (FSK)

a 9.4

INDUSTRIAL NETWORKING

NODEFIELD NETWORK NODEN

OD

EBRANCHN

OD

ES

MA

RT

SE

NS

OR

SM

AR

T S

EN

SO

R

DE

VIC

E N

ET

WO

RK

SMART SENSOR

SMART SENSOR

a 9.5

SOME OF THE STANDARDS

n Ethernet

n Foundation Fieldbus

n Lonwork

n Profibus

n Interbus-S

n Universal Serial Bus (USB)

n CAN-Bus

n Device-Net

n WorldFIP

n P-NET

n HART

n ASI

a 9.6

THE IEEE 1451.2 SENSOR INTERFACE STANDARD

NCAP FIELD NETWORK - OR - DEVICE NETWORK

TII

ST

IM

TEDS

Sensoror

Actuator

n NCAP = Network Capable ApplicationProcessor

n TII = Transducer IndependentInterface

n TEDS = Transducer Electronic Datasheet

n STIM = Smart Transducer InterfaceModule

a 9.7

TRUE "PLUG AND PLAY"

LonworkNCAP

EthernetNCAP

EthernetNCAP

PC withWeb Browser

LonworkNCAP

Ethernet Field Network Lonwork Field Network

Flo

w R

ate

ST

IM

Tem

per

atu

re S

TIM

Pre

ssu

re S

TIM

a 9.8

THE SMART SENSOR

Precision Amplifier

High Resolution ADC

Microcontroller Sensor

Pressure Sensor,RTD, Thermocouple,Strain Gage,etc.

a 9.9

THE EVEN SMARTER SENSOR

SensorMicroConverterTM !

Pressure Sensor,RTD, Thermocouple,Strain Gage,etc.

a 9.10

THE MicroConverter™

High Performance Analog I/O

+

On-Chip FLASH Memory

+

On-Chip Microcontroller

1

2

3

=

MicroConverter™

a 9.11

ANALOG I/O 1

n Dual Σ∆Σ∆ ADCu >16 bitu >100dB SNR (p-p)u Differential Inputsu Prog. Gain Ampu Self-Calibration

n 12bit V-Out DACu < ½ LSB DNL

n Voltage Reference

n Temperature Sensor

n 8 chan SAR ADCu 10 bitu < ½ LSB INL

n 12bit V-Out DACu < ½ LSB DNL

n Voltage Reference

n Temperature Sensor

n 8 chan SAR ADCu 12 bit, 5µsu < ½ LSB INLu DMA modeu Self-Calibration

n Dual 12bit V-Out DACu < ½ LSB DNL

n Voltage Reference

n Temperature Sensor

ADuC816 ADuC812 ADuC810

a 9.12

ON-CHIP FLASH MEMORY 2

n 8K bytes Nonvolatile FLASH Program Memoryu Stores Program and Fixed Lookup Tablesu In-Circuit Serial Programmable or External Parallel Programmableu Read-Only to Microprocessor Core

n 640 bytes Nonvolatile FLASH Data Memoryu User “Scratch Pad” for Storing Data During Program Executionu Simple Read / Write Access Through SFR Space

n Programming Voltage (VPP) Generated On-Chip

ADuC816 ; ADuC812 ; ADuC810

a 9.13

ON-CHIP MICROCONTROLLER 3

n Industry Standard 8052 Coreu 12 Clock Machine Cycle w/ up to 16MHz Clocku 32 Digital I/O Pinsu Three 16bit Counter/Timersu Universal Asynchronous Receiver/Transmitter

(UART) Serial Port

n ...Plus Some Useful Extrasu SPI or I2C Compatible Serial Interfaceu WatchDog Timeru Power Supply Monitoru Timer Interval Counter (ADuC816/810)

ADuC816 ; ADuC812 ; ADuC810

a 9.14

ADuC816 FUNCTIONAL BLOCK DIAGRAM

AINMUX

AINMUX

buf pga Σ∆Σ∆ ADC

ADCcontrol

andcalibration

Σ∆ Σ∆ ADC

ADCcontrol

andcalibration

TEMPsensor

2.5Vbandgapreference

VREFdetect

8K x 8programFLASH

EEPROM

640 x 8user FLASH

synchronousserial interface(SPI or I2C)

8052micro-

controllercore

256 x 8user RAM

watchdogtimer

power supplymonitor

asynchronousserial port(UART)

16 bitcountertimers

timerintervalcounter

OSC &PLL

DACcontrol

DAC1buf

buf

AV

DD

AG

ND

DV

DD

DG

ND

SC

LK

SD

AT

A/

MO

SI

MIS

OS

S

AL

E

PS

EN

EA

RE

SE

T

RxD

TxD

XT

AL

1

XT

AL

2

(primary channel)

(auxilliary channel)

AIN1

AIN2

AIN3

AIN4

VREFIN+

VREFIN–

IEXC1

IEXC2

DAC

T0

T1T2

T2EX

INT0

INT1

–3.5mV/°C

ADuC816

5 6 20 34 47 21 35 48 26 27 14 13 42 41 40 15 16 17 32 33

43 44 45 46 49 50 51 52 1 2 3 4 9 10 11 12 28 29 30 31 36 37 38 39 16 17 18 19 22 23 24 25

910

1112

8

7

3

4

10

22

23

1

2

18

19

P0.

0P

0.1

P0.

2P

0.3

P0.

4P

0.5

P0.

6P

0.7

P1.

0P

1.1

P1.

2P

1.3

P1.

4P

1.5

P1.

6P

1.7

P2.

0P

2.1

P2.

2P

2.3

P2.

4P

2.5

P2.

6P

2.7

P3.

0P

3.1

P3.

2P

3.3

P3.

4P

3.5

P3.

6P

3.7

a 9.15

ADuC816 - PRIMARY SPECIFICATIONS

n ADC : INL - ± 30ppmSNR (p-p) - >102dB (17 Noise Free Bits)Input Range - ± 20mV to ± 2.56VConv. Rate - 5.4Hz to 105Hz

n DAC : DNL - ± ½LSBOutput Range - 0 to VREF -or- 0 to VDDSettling Time - <4µs

n Power : Specified for 3V or 5V Operation5V 3V

Normal 7mA 3mAIdle 4.5mA 1.5mAPowerdown <20µA <20µA

a 9.16

ADuC812 FUNCTIONAL BLOCK DIAGRAM

AINMUX

T/H 12-bit ADC ADC

controland

calibration

TEMPsensor

2.5Vbandgapreference

8K x 8programFLASH

EEPROM

640 x 8user FLASH

synchronousserial interface(SPI or I2C)

8052micro-

controllercore

256 x 8user RAM

watchdogtimer

power supplymonitor

asynchronousserial port(UART)

16 bitcountertimers

OSC

DACcontrol

DAC1 buf

AV

DD

AG

ND

SC

LK

SD

AT

A/

MO

SI

MIS

O

SS

AL

E

PS

EN

EA

RE

SE

T

RxD

TxD

XT

AL

1

XT

AL

2

ADC0

ADC1

ADC3ADC4

VREF

DAC1

T0

T1T2

T2EX

INT0

INT1

–3.5mV/°C

ADuC812

ADC2

ADC5ADC6

ADC7

CREF

DAC0 buf DAC0

buf

CONVST

hardware 43 44 45 46 49 50 51 52 1 2 3 4 11 12 13 14 28 29 30 31 36 37 38 39 16 17 18 19 22 23 24 25

23

5

1

2

3

4

11

12

13

14

8

7

6 20 34 47 21 35 48 26 27 19 12 42 41 40 15 16 17 32 33

9

10

22

23

1

2

18

19

P0.

0P

0.1

P0.

2P

0.3

P0.

4P

0.5

P0.

6P

0.7

P1.

0P

1.1

P1.

2P

1.3

P1.

4P

1.5

P1.

6P

1.7

P2.

0P

2.1

P2.

2P

2.3

P2.

4P

2.5

P2.

6P

2.7

P3.

0P

3.1

P3.

2P

3.3

P3.

4P

3.5

P3.

6P

3.7

DV

DD

DG

ND

a 9.17

ADuC812 - PRIMARY SPECIFICATIONS

n ADC : INL - ± ½LSBSNR (p-p) - >70dBInput Range - 0 to VREFConv. Time - <5µs (200kSPS)

n DAC : DNL - ± ½LSBOutput Range - 0 to VREF -or- 0 to VDDSettling Time - <4µs

n Power : Specified for 3V or 5V Operation5V 3V

Normal 18mA 12mAIdle 10mA 6mAPowerdown <50µA <50µA

a 9.18

MicroConverter™ DESIGN SUPPORT

MicroConverterTM

Web Site

QuickStartTM

Development Kit

Third PartyDevelopment Tools

1

2

3

a 9.19

MicroConverter™ WEB SITE

www.analog.com1

n Data Sheets

n Application Notes

n 8051 Reference Material

n Free Windows MicroConverterTM Simulator

n Free Keil ‘C’ Compiler (2K limited version)

a 9.20

MicroConverter™ - QuickStart™ DEVELOPMENT KIT

n Documentationu User’s Guideu Datasheetu Tools Tutorialu Quick Reference Guide

n Evaluation Boardu RS-232 Serial Commsu 32K External SRAMu Buffered Analog I/O

n Regulated Power Supply

n Serial Port Cable

n Software

u Metalink Assembleru ‘C’ Compiler (Limited 2K)u Windows Simulatoru Serial Downloaderu Windows Debuggeru Example Code

QuickStartTM

2

a 9.21

MicroConverter™ - THIRD PARTY DEVELOPMENT TOOLS

n Keil Compileru A full function windows based ‘C’ compiler environment featuring

a simulator for source and assembly level debugging.

n MetaLink Emulatoru A high end in circuit emulation system offering a complete

windows based environment for in-system debug sessions.

Power Tools3

All tools will fully integrate with each MicroConverter product

The First Two of Many ThirdParty Tools to Fully SupportMicroConverterTM Products:

a 9.22

MicroConverter™ PRODUCT ROADMAP

n Larger FLASH Memory Capacity(Data and Program)

n Hardware CommunicationsInterface Enhancements(CAN Bus, USB Bus)

n Increased MicrocontrollerHorsepower

TIME

1

ADuC812-

8 Channel12 bit ADC

-Dual DAC

3

ADuC810-

Low Cost-

10 bit ADC,Dual DAC

2

ADuC816-

Dual 16 bit +Σ∆Σ∆ ADC

-Single DAC

. . . . Future Products May Include:

. . . .