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This practical temperature controller controls the temperature of any device according to its requirement for any industrial application. It also displays the temperature on an LCD displays in the range of –55°C to +125°C. At the heart of the circuit is the microcontroller from 8051 family which controls all its functions. It is important to control the speed of DC motor where precision and protection are essence. Here we will use a technique called PWM (pulse width modulation) to control the speed of DC motor
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Industrial Temperature
Controller
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Introduction
Industrial Temperature Controller
We can achieve speed control of DC motor using mechanical or electrical techniques but they require large size hardware to implement but Microcontroller based system provides easy way to control the speed of DC motor. The speed of DC motor is directly proportional to the voltage applied across its terminals. Hence, if voltage across motor terminal is varied, then speed can also be varied. PWM (Pulse Width Modulation) wave can be used to control the speed of the motor
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Industrial Temperature Controller
Block Diagram
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Industrial Temperature Controller
Hardware Requirementso 8051 series Microcontrollero 7-Segment Displayso Temperature Sensoro Transformero Crystalo Diodeso Voltage Regulatoro LEDo Resistorso Capacitorso Push Buttonso Relayo Lamp
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Industrial Temperature Controller
Software Requirements
Keil compiler
Language: Embedded C or Assembly
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Industrial Temperature Controller
Micro Controller Compatible with MCS®-51 Products
8K Bytes of In-System Programmable (ISP) Flash Memory
4.0V to 5.5V Operating Range
Crystal Frequency 11.0592MHZ
Three-level Program Memory Lock
256 x 8-bit Internal RAM
32 Programmable I/O Lines
Three 16-bit Timer/Counters
Eight Interrupt Sources
Full Duplex UART Serial Channel
Watchdog Timer
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Industrial Temperature Controller
PWM – Plus Width Modulation
The PWM switching frequency has to be much faster than what would
affect the load, which is to say the device that uses the power.
The term duty cycle describes the proportion of on time to the regular
interval or period of time.
A low duty cycle corresponds to low power, because the power is off for
most of the time. Duty cycle is expressed in percent, 100% being fully
on.
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Industrial Temperature Controller
PWM Application
Telecommunications
Power delivery
Voltage regulation
Audio effects and amplification.
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Industrial Temperature Controller
DC- MOTOR
A DC motor is an electric motor that runs on direct current (DC) electricity. In any electric motor, operation is based on simple electromagnetism.
A simple 2-pole DC electric motor (here red represents a magnet or winding with a "North" polarization, while green represents a magnet or winding with a "South" polarization).
Every DC motor has six basic parts -- axle, rotor (a.k.a., armature), stator, commutator, field magnet(s), and brushes.
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Industrial Temperature Controller
How to Operate PWM based DC Motor Speed Control Circuit using Microcontroller?
Connect 12V battery or adaptor to the development board.
Switch on the supply.
Keep the programming switch in prgm mode.
Burn hex file to the atmega8 controller with the help of serial cable.
Now switch off the supply.
Connect PC0, PC1 pins of controller to the switches.
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Industrial Temperature Controller
How to Operate PWM based DC Motor Speed Control Circuit using Microcontroller?
Connect PB3 pin to the DC motor.
Now switch on the supply and press switch sw1 and observe motor. It runs with full speed.
If you press switch sw2 motor runs with half speed.
Switch off the supply.
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Industrial Temperature Controller
PWM Based DC Motor Speed Control using Microcontroller Circuit Principle:
The Principle to control the speed of the motor by varying the duty cycle of the pulse applied to it (popularly known as PWM control).
It uses two input buttons interfaced to the microcontroller, which are used to control the speed of motor.
PWM (Pulse Width Modulation) is generated at the output by the microcontroller as per the program.
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Industrial Temperature Controller
PWM Based DC Motor Speed Control using Microcontroller Circuit Principle:
The average voltage given or the average current flowing through the motor will change depending on the duty cycle (ON and OFF time of the pulses).
So the speed of the motor will change.
A motor driver IC is interfaced to the microcontroller for receiving PWM signals.
It delivers desired output for speed control system of a small DC motor.
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Industrial Temperature Controller
Advantages
Using this PWM method, we can save the power.
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Industrial Temperature Controller
Applications
Used in industries to control the speed of motors.
Used in shopping malls.
We can use this concept to control the light intensity.
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Industrial Temperature Controller
Conclusion
This practical temperature controller controls the temperature of any device according to its requirement for any industrial application. It also displays the temperature on an LCD displays in the range of –55°C to +125°C. At the heart of the circuit is the microcontroller from 8051 family which controls all its functions.
