Electronic Instrumentation & Electronic Instrumentation & PLCPLC

DKT 314DKT 314

Digital thermometer LCD display using LM35

Lecturer: En Mat Nor Mohamad B Ismail

En Zulkifli Husin

SYNOPSISSYNOPSISDigital thermometer designed for

measuring temperature in three scales (Fahrenheit Celsius and Kelvin )

Temperature was measured by LM35DZThe 0804 analog to digital converter

(ADC), convert the dc output provided by LM35D and sends to microcontroller (AT89S52)

The program write in C languageMicrocontroller read binary output from

the A/D converter, performs ASCII code, and sends to a 16x2 line LCD display

OBJECTIVEOBJECTIVEAbility to apply the basic concept of

electronic instrumentationAbility to under stand the basic

concept of electronic instrumentation

Ability to integrate basic sensor temperature circuit and LCD display with 8051

BLOG DIAGRAMBLOG DIAGRAM

LM35 FILTER AMP ADC

8051

Display

PART 1 –LM35PART 1 –LM35

-Voltage increase 10mV/ ⁰C-supply voltage 5V

PART 2- FILTERPART 2- FILTER

LOW PASSFILTERVout=1/2∏RC

R=100kΩ,C=0.002mFVout=795.77Hz

PART 3- AMPLIFIERPART 3- AMPLIFIER

Gain = 1+(R2/R1)R1=10kΩ,R2=10Ω

Gain= 1.001

PART 4 –ADC 0804PART 4 –ADC 0804

Vref=not connectedStep size=19.53mVVout= Vin/ Step size

Full Schematic DiagramFull Schematic Diagram

PROBLEMSPROBLEMSAmplifier – the theoretical not equal

to practical amplifierUneasy to stable the temperature

value.To find the best filter for the

project.

CONCLUTIONCONCLUTIONObjective for this project has

archive.Learn the basic of electronic

instrumentationThis project can control anything

that use this system.