Capston project ITT

05/01/2023 TEMPERATURE CONTROLLER ITT TECHNICAL INSTITUTE HILLIARD 2016 1

GENERIC TEMPERATURE CONTROLLER

Capstone ProjectMarch Quarter 2016

Muhammad Abdul Hafiz Steven thrasher Ibrahim Nor Darrell Pollard

Project advisor David Ney



THE PURPOSE

Temperature controllers are needed in any situation requiring a given temperature be kept stable. This can be in a situation where an object is required to be heated, cooled or both and to remain at the target temperature (set-point), regardless of the changing environment around it. So a temperature controller is a device used to hold a desired temperature at a specified value.


THE PURPOSE

The simplest example of a temperature controller is a common thermostat found in homes. For instance, a hot water heater uses a thermostat to control the temperature of the water and maintain it at a certain commanded temperature.


THE PURPOSE Temperature controllers are also used in ovens. When a temperature is set for an oven, a controller monitors the actual temperature inside of the oven. If it falls below the set temperature, it sends a signal to activate the heater to raise the temperature back to the set-point. Thermostats are also used in refrigerators. So if the temperature gets too high, a controller initiates an action to bring the temperature down.


THE PURPOSE

The temperature controller is very important technique in the laboratories of material science and the industry, because of that we (Muhammad, Ibrahim, Darrell and Steven ) will perform the project under title: “GENERIC TEMPERATURE CONTROLLER “for the capstone project /ET2799 Electrical Engineering Technology.


THE GOALS

There are two fundamental types of temperature control; open loop and closed loop control. Open loop is the most basic form and applies continuous heating/cooling with no regard for the actual temperature output. It is analogous to the internal heating system in a car. On a cold day, you may need to turn the heat on to full to warm the car to 75°. However, during warmer weather, the same setting would leave the inside of the car much warmer than the desired 75°.


THE GOALS

Open loop control block diagram


THE GOALS

Closed loop control is far more sophisticated than open loop. In a closed loop application, the output temperature is constantly measured and adjusted to maintain a constant output at the desired temperature. Closed loop control is always conscious of the output signal and will feed this back into the control process. Closed loop control is analogous to a car with internal climate control.


THE GOALSIf you set the car temperature to 75°, the climate control will automatically adjust the heating (during cold days) or cooling (during warm days) as required to maintain the target temperature of 75°.

Closed loop control block diagram


THE GOALSOur chosen goal is achieving closed loop temperature control, because it gives us chance to control heating and cooling processes with the ability of defining the value of temperature at any time during the experiment.


THE BENEFITS

1. This project can be used in Home.2. This project can be used in Industry.3. This will help in saving the energy / electricity.4. We can monitor changing temperature depending on time.5. We can draw graphs of variations in these parameters using computer.


OBJECTIVES

All controllers have several common parts. For starters, controllers have inputs. The inputs are used to measure a variable in the process being controlled. In the case of a temperature controller, the measured variable is temperature.


INPUTS

Temperature controllers can have several types of inputs. The type of input sensor and signal needed may vary depending on the type of controlled process. Typical input sensors include thermocouples and resistive thermal devices (RTD's), and linear inputs such as mV and mA. Typical standardized thermocouple types include J, K, T, R, S, B and L types among others.


INPUTS Controllers can also be set to accept an RTD as a temperature sensing input. A typical RTD would be a 100Ω platinum sensor.

Alternatively, controllers can be set to accept voltage or current signals in the millivolt, volt, or milliamp range from other types of sensors such as pressure, level, or flow sensors. Typical input voltage signals include 0 to 5VDC, 1 to 5VDC, 0 to 10VDC and 2 to 10VDC. Controllers may also be set up to accept millivolt signals from sensors that include 0 to 50mVDC and 10 to 50mVDC. Controllers can also accept milliamp signals such as 0 to 20mA or 4 to 20mA.


INPUTS

A controller will typically incorporate a feature to detect when an input sensor is faulty or absent. This is known as a sensor break detect. Undetected, this fault condition could cause significant damage to the equipment being controlled. This feature enables the controller to stop the process immediately if a sensor break condition is detected.

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OUTPUTS

In addition to inputs, every controller also has an output. Each output can be used to do several things including control a process (such as turning on a heating or cooling source), initiate an alarm, or to retransmit the process value to a programmable logic controller (PLC) or recorder.

TEMPERATURE CONTROLLER ITT TECHNICAL INSTITUTE HILLIARD 2016


OUTPUTS

Typical outputs provided with temperature controllers include relay outputs, electro -mechanicl drivers, triac, and linear analog outputs. A relay output is usually a single-pole double-throw (SPDT) relay with a DC voltage coil. The controller energizes the relay coil, providing isolation for the contacts. This lets the contacts control an external voltage source to power the coil of a much larger heating contactor.


OUTPUTS Analog outputs are provided on some controllers which put out a 0–10V signal or a 4–20mA signal. These signals are calibrated so that the signal changes as a percentage of the output. For example, if a controller is sending a 0% signal, the analog output will be 0V or 4mA.

When the controller is sending a 50% signal, the output will be 5V or 12mA.

When the controller is sending a 100% signal, the output will be 10V or 20mA.


OUTPUT


CONSTRAINTS We hope that, during next six weeks, we will complete hardware and software of our project.

We defined elements what we need as the following: Micro controller 8051triniar Personal computer Interface between PC and Micro controller Temperature sensor EM relay Heaters metallic cabinet as oven body Power supply.


THE PRACTICE PART




INTERFACE LM35 TEMPERATURE SENSOR WITH 8051 (AT89C51)


FLOW-CHART


THE PROGRAMS


THE PROGRAM void disp_temp(double num) //displays number on LCD { unsigned char UnitDigit = 0; //It will contain unit digit of

number unsigned char TenthDigit = 0; //It will contain 10th position

digit of number unsigned char HundDigit = 0; //It will contain 100th position

digit of number unsigned char decimal=0; //It will contain the decimal

position of number int point; point=num*10; HundDigit=(num/100); if( HundDigit != 0) // If it is zero, then don't display lcddata(HundDigit+0x30); // Make Character of HundDigit and then display it on LCDTenthDigit = num - HundDigit*100; // Findout Tenth Digit TenthDigit = TenthDigit/10; if (HundDigit==0 && TenthDigit==0){} // If it is

zero, then don't display else

lcddata(TenthDigit+0x30); // Make Char of TenthDigit and then display it on LCD

UnitDigit = num - HundDigit*100; UnitDigit = UnitDigit - TenthDigit*10; lcddata(UnitDigit+0x30); // Make Char of UnitDigit and then

display it on LCD lcddata('.'); decimal=(point%10); lcddata (decimal+0x30); // Make Char of Decimal Digit and then

display it on LCD lcddata(' '); lcddata('C'); } void read(){ // Displays "READING" while controller reads from ADC lcdcmd(0x0E); //turn display ON for cursor blinking lcdcmd(0x01); //clear screen lcdcmd(0x06); //increment cursor lcddata('R');lcddata('E');lcddata('A');lcddata('D');lcddata('I');lcddata('

N');lcddata('G');lcddata(' '); }


THE PROGRAM

lcddata('R');lcddata('E');lcddata('A');lcddata('D');lcddata('I');lcddata('N');lcddata('G');lcddata(' ');

} void main() { P0=0x00; //intialize port 0 to low use while controller reads the

temperature from //ADC read(); // show reading on LCD while controller reads from ADC while(1){ // use for checking errors while reading the value from

ADC newtemp=adc(); //reads first value from ADC delay(60); //waits 60 msec pass1=adc(); // reads the Second value from ADC delay(60); // waits 60 msec if (newtemp==pass1){ //compare first and second value break; // if first and second value is same breaks the loop } }

while(1) //enters in the permanent loop { T=160; //set reference voltage acting multiplier

factor for temperature accuration newtemp=(((newtemp*T)/255)); //converts the temperature value

according to reference adjusted in decimal lcdcmd(0x0E); //turn display ON for cursor blinking lcdcmd(0x01); //clear screen lcdcmd(0x06); //increment disp_temp(newtemp); //show temperature delay(300); //waits 3sec before re-measure the value of temperature while(1){ // re-measure the value from ADC but this time double

check newtemp=adc(); delay(60); pass1=adc(); delay(60); pass2=adc(); if (newtemp==pass1){ }


THE PROGRAM if(pass1==pass2){

break; }

} // end ADC while loop } Interfacing ADC to 8051 MC #include <reg51.h> #define ALEP3_4 #define OE P3_7 #define START P3_5 #define EOC P3_6 #define SEL_A P3_1 #define SEL_B P3_2 #define SEL_C P3_3 #define ADC_DATA P1

void main() { unsigned char adc_data; /* Data port to input */ ADC_DATA = 0xFF; EOC = 1; /* EOC as input */ ALE = OE = START = 0; while (1) { /* Select channel 1 */ SEL_A = 1; /* LSB */ SEL_B = 0; SEL_C = 0; /* MSB */


THE PROGRAM /* Latch channel select/address */ ALE = 1; /* Start conversion */ START = 1; ALE = 0; START = 0;

/* Wait for end of conversion */ while (EOC == 1); while (EOC == 0); /* Assert Read signal */ OE = 1; /* Read Data */ adc_data = ADC_DATA; OE = 0; /* Now adc data is stored */ /* start over for next conversion */ } }

C code for connecting relay with 8051 mc #include <reg51.h> //Define 8051 registers #include<stdio.h> sbit relay1 = P0^4; sbit relay2 = P0^5; void DelayMs(unsigned int); //Delay function //---------------------------------- // Main Program //---------------------------------- void main (void) { P2 = 0; //Initialize Port while(1) //Loop Forever { relay1 = 1; //Relay1 - ON relay2 = 0; //Relay2 - Off DelayMs(200); //Delay 20msec


THE PROGRAM relay1 = 0; //Relay1 - Off

relay2 = 1; //Relay2 - ON DelayMs(200); //Delay 20msec } } //--------------------------------- // Delay Function //--------------------------------- void DelayMs(unsigned int n) { unsigned int i,j; for(j=0;j<n;j++) { for(i=0;i<1000;i++); } }


Thank you for your patience.

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Capston project ITT