PID CONTROLLER
PID is "proportional", "integral" and "derivative" controller. I've
choose PID controller is because the simple structure of PID itself,
easy to understand and possible to do the manual tunning as well as a
PID calculates an "error" value as the difference between
a measured process variable and a desired set point. The controller attempts to
minimize the error by adjusting the process control inputs. The PID controller is mostly approach to the industrial field.
WHY USED IT?
- It helps get your output temperature where you
want it, in a short time, with minimal overshoot, and with little error.
- PID is the main popular method of control in industry
since it is probably the most extensively used method in industrial
process control applications.
PID
controller structured is basis on three most important
controller structures which there are proportional, integral and
derivative
controller which include in single packages of controller. The PID
controller also have some disadvantages that be a factor which lead to
be unsatisfactory in tuning PID controller.
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PIC stands for "Peripheral Interface Controller". This powerful 200 nanosecond instruction execution yet easy to program that only 35 single word instruction CMOS FLASH based 8-bit microcontroller packs Microchip's powerful PIC architecture into a 28 pin package. It's also low cost and high clock speed. It's code is extremely efficient, allowing the PIC to run with typically less program memory than its lager competitors. A simple instruction set and seamless migration between product families make this PIC the logical choice for design requiring flexibility and performance. One of the advantages is that yet easy to program that only 35 single word instructions CMOS FLASH based 8 bit microcontroller packs Microchip's powerful PIC architecture into a 28 pin package.
SPECIAL MICROCONTROLLER FEATURES:
- Precision Internal Oscillator:
- factory calibrate to 1%
- software selectable frequency range of 8 MHz to 32 MHz
- software tunable
- two-speed start up mode
- fail-safe clock monitoring for critical applications
- clock mode switching during operation for low power operation
- power saving sleep mode
- power on reset (POR)
- selectable brown out reset (BOR) voltage
- extended watchdog timer (WDT) with its own on-chip RC oscillator for reliable operation
- self-reprogrammable under software control
- programmable code protection
- capture/compare/PWM (CCP) module
THANK YOU
On this project title, temperature sensor as the input to sense the whole temperature during the working process. Temperature
sensors are needed to sense the temperature heat that will occur during the
temperature system is activated and to beware about the high temperature. This is
because the high temperature will effect the system.
Why Monitor Temperature?
"COMPONENTS MAY BE DAMAGED IF THE TEMPERATURE FALLS OUTSIDE THE OPERATING RANGE AND THEN THE OPERATION WILL BE FAILURE"
At first I have to search and comparing a certain
temperature sensors that available in the market that suit the characteristic of the project function before deciding to choose
either one.
Desired Sensor Characteristics
i. RESISTANCE TEMPERATURE DETECTOR (RTD)
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iii. THERMOCOUPLE SENSORS
iv. THERMISTOR
From all the temperature sensor above, temperature sensor LM35 is one of the most accurate and economical integrated circuit temperature sensors that available in market. The LM35 series are precision integrated circuit
temperature sensors, whose output voltage is linearly proportional to the
Celsius temperature. The LM35 thus has an advantage over linear
temperature sensors calibrated in ° Kelvin, as the user is not required to
subtract a large constant voltage from its output to obtain convenient
Centigrade scaling. The LM35 also does not require any external calibration or
trimming to provide typical accuracies of ±¼°C at room temperature and ±¾°C
over a full -55 to +150°C temperature range.
APPENDIX : DATA SHEET : http://www.ti.com/lit/ds/symlink/lm35.pdf
THANK YOU
This week is an Eid-ul-Fitr holidays for all student in UniKL BMI. I will take this time to search more information relate to my project title.
1. THE DESIGN OF TEMPERATURE CONTROL SYSTEM USING PIC
18F4620
Large scales of application are dedicated to
control the temperature in a realistic environment suitable to various needs.
In order to obtain the optimum performance it would be advantageous to provide
a temperature control structure by providing a safer cooling or heating system
with better performances in terms of energy efficiency, flexibility and
portability. Extensively research has been made on heating control because of
the necessity in practical applications. In this paper the idea focuses on a
simple process that could be suitable to educational application in order to
illustrate different control design aspects. Moreover, the designed plant is a
low cost application with components ease of access. The plant consists in a
cooler, a resistance, a sensor and a microcontroller that are encapsulated in a
small testing room. The analog temperature sensor LM335 will offer information
of the current state of degrees at every sampling time. To relieve the
performance of the proposed cooling system it is necessary to increase the test
room temperature with an electrical heat resistor made of nickel. The heat
discharge in the small test room will be fixed by limiting the value of the
current with a variable voltage actuator for alternative current. The function
of the cooler will be to decrease the air temperature from the test room. The
control architecture allows for the users to implement their knowledge of
control engineering in an easy way due to process access by a friendly design. The
implemented PID controller on PIC18F4620 can offer zero steady state error even
if a load disturbance is introduced in the test room. In the cases where the
plant response is slow, it may be possible to decrease the processor speed and
save power.
2. AUTOMATIC ROOM TEMPERATURE CONTROL
The proposed system would use heated water to
control the temperature of the room. Heated water would be circulated in a room
by motorized pump. The motor would be controlled by a microcontroller. A
thermistor would provide the temperature input to the microcontroller. The
microcontroller will process the raw input, and then turn the motor on/off by
comparing the current temperature with the required temperature set by the
user. The proposed has been designed to control the temperature of a medium
sized room. This is achieved by using a conventional water pump to circulate
the water through pipes. The water is passed through an instant geyser which
heats it up. Instant geysers fire-up when water is passed through them,
otherwise they are dormant. This system controls the circulation of water by
controlling the motor, which in turn controls the geyser. Therefore, efficiency
and economy of both gas and electricity is achieved through this method of
heating. Another application by some modification is the incubator. Incubator
requires a constant temperature to be maintained. And this system provides an
efficient mechanism for controlling the temperature in an incubator.
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SYSTEM OVERVIEW |
Features to make an improvement
From all the above previous project, it usually used PIC16F876A Microcontroller and microcontroller 8051 to control the NPN transistor (BD 135). To make an improvement from others, I'm planning to change a little bit for the controller. The idea came when doing the research of the project title, the idea is to implementing PID controller to maintain the temperature by controlling the flow of air system inside the control panel. The project will includes identifying on how PID controller can
be implemented in the low cost system in maintaining the safe operation temperature controller to share the product to the purpose of studies in the educational field. For all work that wanted to be done, there must be a process to implement the task. So, I've decided to separate the process of work into three main part.
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PROCESS OF WORK
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In order to achieve the objective of these project, all work must be arranged neat and smooth.
MICROCONTROLLER
A
microcontroller is a small computer on a single integrated circuit
containing a processor core, memory, and programmable input or output
peripheral. Microcontrollers are design for embedded applications.
Microcontroller is one of the microchip that emphasizes self-sufficiency
and cost effectiveness, in contras to a general purpose microcontroller
usually used in personal computer.
WHY CHOOSE MICROCONTROLLER?
"IT CAN REDUCE THE SIZE AND COST."
THANK YOU