PLC Based Automatic Air Conditioning Control SystemPLC BASED AUTOMATIC AIR CONDITIONING CONTROL SYSTEM WOLLO UNIVERSITY KIOT ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT (INDUSTRIAL CONTROL STREAM) SUBMITED BY: 1. ABRHA WELDEAREGAY………………..KIOT/0063/04 2. AREGAY ABRHA…………………………KIOT/1243/04 3. 4. 5. 6. ABEBA NIGUS…………………………….KIOT/0032/04 AMSAL ANTEHUNEGN………………….KIOT/0149/04 ABRHET HAGOS………………………….KIOT/0060/04 ANDINET YESUF…………………………KIOT/0152/04 ADVISOR: Mr.MANOHAR MAY 2015 1 | Page PLC Based Automatic Air Conditioning Control System ABSTRACT This project aim is to design an automatic air conditioning system control technique for a conventional unitary home, hospital, school etc…..air conditioner using Programmable Logic Controller (PLC) approach to achieve both the steadiness in this area in temperature and saving the consumption energy. Acknowledgment First of all, we would like to thank our GOD, and to our respected advisor Mr. manohar for their professional guidance, advice, motivation, endurance and encouragements during their supervision period. And also all our families for their motivational and financial help, and then thanks to the other members and staff of the Focus area of Industrial control Engineering. The guidance and support received from all the members who contributed and who are contributing to this project, was vital for the success of the project. We are grateful for their constant support and help. Contents ABSTRACT................................................................................................................... 2 Acknowledgment........................................................................................................ 2 LIST OF TABLE............................................................................................................ 3 LIST OF FIGUER........................................................................................................... 3 2 | Page PLC Based Automatic Air Conditioning Control System CHAPTER ONE.............................................................................................................. 5 INTRODUCTION........................................................................................................... 5 1.1 Background............................................................................................................... 5 1.2 Principles of automatic air conditioning............................................................................ 5 1.3 Objectives of the project............................................................................................... 5 1.4 Significance of the project............................................................................................. 6 1.5 Problems statement...................................................................................................... 6 1.6 Scope of the project..................................................................................................... 6 1.7 Organization of the project............................................................................................ 7 CHAPTER TWO............................................................................................................. 8 LITERATURE REVIEW................................................................................................... 8 2.1 Control system........................................................................................................... 8 2.2 Introduction to Programmable Logic Controller “PLC”.........................................................9 2.3 The Role of the Programmable Logic Controllers (PLC)........................................................9 2.4 Basic parts of PLC:-..................................................................................................... 9 2.4.1 Processors module:-............................................................................................. 10 2.4.2 Memory............................................................................................................ 10 2.4.3 Input modules..................................................................................................... 10 2.4.4 Output modules:-................................................................................................. 11 2.4.5 A programming unit............................................................................................. 11 2.4.6 The power supply................................................................................................ 11 2.6 Characteristic Functions of a PLC..................................................................................12 2.7 Processing Methods................................................................................................... 12 2.7.1Cyclic operation................................................................................................... 12 2.8 LOGO.................................................................................................................... 12 2.8.1 Programming languages........................................................................................ 12 CHAPTER THREE........................................................................................................ 14 METHDOLOGY........................................................................................................... 14 3.1 Input Functions......................................................................................................... 15 3.2 Output functions....................................................................................................... 16 3.3 Control functions...................................................................................................... 16 3.5 Hard-ware design of measuring systems..........................................................................17 3.6 Air conditioning system.............................................................................................. 17 3 | Page PLC Based Automatic Air Conditioning Control System 3.6.1 Components of an air conditioner with their application.................................................18 3.6.2 Air conditioner controls and features.........................................................................20 3.6.3 Operation principle.............................................................................................. 20 3.6.4 Communication................................................................................................... 22 3.7 Software development................................................................................................ 23 3.7.1 Programming structure.......................................................................................... 24 3.8 Proper selection of sensors and signal conditioning element..................................................24 3.8.1 Sensor Selection.................................................................................................. 24 3.8.2 Temperature sensor LM35...................................................................................... 25 3.8.4 Humidity sensor.................................................................................................. 25 RESULTS & DISCUSSION............................................................................................. 26 4.1 HVAC control system................................................................................................. 26 4.2 Requirements for Air conditioning.................................................................................26 4.3 Connection of PLC.................................................................................................... 27 4.4 Air Conditioning....................................................................................................... 31 4.5 Humidity control system............................................................................................. 32 4.6 Lighting control system.............................................................................................. 35 CHUPTER FIVE........................................................................................................... 40 CONSLUSION AND RECOMMENDATION.......................................................................40 5.1 Project Conclusion.................................................................................................... 40 5.2 Recommendation...................................................................................................... 41 REFERENCES............................................................................................................. 42 APPENDICES.............................................................................................................. 43 LIST OF TABLE Table 1.1 material required …………………………………………………………….…...8 Table 4.1 air conditioning input/output ………………………………………………….58 Table 4.2 humidity input/output ………………………………………………………….63 Table 4.3 light control input/output ……………………………………………………….66 4 | Page PLC Based Automatic Air Conditioning Control System LIST OF FIGUER Figure 1 Flow chart project developments...................................................................................................7 Figure 2 conrol of temperature....................................................................................................................9 Figure 3 control of temperature.................................................................................................................10 Figure 4 control of temperature.................................................................................................................10 Figure 5 control of temperature.................................................................................................................11 Figure 6 Basic structure of plc...................................................................................................................13 Figure 7 Memory and processors in the CPU module...............................................................................14 Figure 8 input modules..............................................................................................................................15 Figure 9 output module..............................................................................................................................16 Figure 10 Power Supplies in a PLC System..............................................................................................17 Figure 11 Standard PLC Scan Cycle..........................................................................................................19 Figure 12 cyclic operation processing method...........................................................................................20 Figure 13 the difference of LAD and FBD................................................................................................21 Figure 14 The Siemens LOGO! PLC.........................................................................................................22 Figure 15 PLC based control system.........................................................................................................23 Figure 16 Block diagram...........................................................................................................................24 Figure 17 Circuit diagram of automatic air condition................................................................................28 Figure 18 physical part of air conditioning system....................................................................................30 Figure 19 schematic diagram of air conditioning system...........................................................................31 Figure 20 Free body diagram of air conditioning......................................................................................34 Figure 21 Operational chart.......................................................................................................................36 Figure 22 Interfacing of hardware and software components of logo plc control......................................37 Figure 23 Software flow chart...................................................................................................................40 Figure 24 HVAC control system flow chart...............................................................................................43 Figure 25 humidity control flow chart.......................................................................................................44 Figure 26 LM35 sensor..............................................................................................................................46 Figure 27 LM35 sensor in board................................................................................................................47 Figure 28 Photo sensor..............................................................................................................................48 Figure 29 HC 20 Humidity sensor.............................................................................................................49 Figure 30 Air Flow Sensor (90 529 673/90 543 282).................................................................................50 Figure 31 Air Flow Sensor (90 529 673/90 543 282).................................................................................50 Figure 32 Motion sensor............................................................................................................................51 Figure 33 Comparing signal conditioning.................................................................................................52 Figure 34 analog to digital converter......................................................................................................53 Figure 35 flow chart of ADC.....................................................................................................................54 Figure 36 Block diagram of DAC..............................................................................................................55 Figure 37 Figure 38 LOGO! Wiring..........................................................................................................57 Figure 39 previous solution.......................................................................................................................57 Figure 40 Ladder diagram of air conditioning...........................................................................................59 Figure 41 Air conditioning in FBD............................................................................................................60 Figure 42 Ladder diagram of air conditioning...........................................................................................61 Figure 43 Air conditioning in FBD................................................................................................62 Figure 44 Ladder diagram of humidity......................................................................................................63 5 | Page ...................................................................69 Figure 48 FBD of light control.....64 Figure 46 Ladder diagram of the overall air conditioning system........................................................................................................................................................................PLC Based Automatic Air Conditioning Control System Figure 45 Humidity in FBD.............................................................................................66 Figure 47 Ladder diagram of light controling.....69 6 | Page .................................................. different options for managing air and using the related elements of automation and control laws. where reeds were hung in windows and were moistened with trickling water. Carrier. The first modern electrical air conditioning unit was invented by Willis Carrier in Buffalo. air conditioning can refer to any form of technological cooling. humidity and air purity degree) to create the comfort and suitable conditions for living and working in an air conditioned environment. Residential sales expanded dramatically in the 1950s. as defined by its temperature and moisture content. or disinfection that modifies the condition of air.1 Background The basic concept behind air conditioning is to have been applied in ancient Egypt. a native of Angola. air conditioning came to be used to improve comfort in homes and automobiles as well. is changed. 1. After graduating from Cornell University. ventilation.3 Objectives of the project The main objective of an air conditioning system is to fulfill the requirements in terms of air quality (temperature.2 Principles of automatic air conditioning Air conditioning is the process whereby not only cooling but also the condition of air. Modern air conditioning emerged from advances in chemistry during the 19th century. found a job at the Buffalo Forge Company. More generally.PLC Based Automatic Air Conditioning Control System CHAPTER ONE INTRODUCTION 1. heating. and the first large-scale electrical air conditioning was invented and used in 1902 by Willis Havilland Carrier. 1. This is achieved by a combination of basic air processing. 7 | Page . New York. New York. Over time. Air conditioning is the process of altering the properties of air (primarily temperature and humidity) to more favorable conditions. To minimize time wastage in every activities To build a working prototype of an automatic air-conditioning control system using PLC software called logo. 1. To make the room temperature at a comfortable level. air conditioning and other systems. energy efficiency and security. improving the life quality and avoiding special aid expenses. A healthy home creation (without contaminant materials) Home life span increases To control every condition of the building automatically 1. regardless of the weather conditions outside. This kind of systems is particularly useful for the disabled or elderly.5 Problems statement Since our environmental temperature increase due to so many factors we try to solve this increment of temperature by design an automatic air conditioner system to settle the increment of temperature to its standard value in order to bring human life in a comfortable way of life by using software called LOGO (semen) PLC. To achieve both the steadiness in temperature and saving the consumption of energy.PLC Based Automatic Air Conditioning Control System This project aim is: To design an automatic air conditioning system control technique for a conventional unitary home. hospital. school air conditioner using Programmable Logic Controller (PLC).4 Significance of the project This kind of systems control lighting. in order to improve comfort. 8 | Page . and humidity in the industry automatically using software called logo plc. Our focus of this project is controlling of air (temperature). light.PLC Based Automatic Air Conditioning Control System 1. methodology.6 Scope of the project The PLC is used as the control technique to control the air condition of the room as a result the speed of the fan accordingly. Materials Quantity Pump motor Fan motor Temperature sensor LM35 02 03 03 Humidity sensor 01 Pressure sensor 01 Light sensor (LDR ) 01 Lamp 05 Simple switches 04 Emergency switch 02 PLC module 01 Timer Visual display PLC software 02 01 01 Table 1.1 material required 9 | Page . Experiment will be conducted to test the PLC program. The test apparatus will be equipped with a LOGO PLC linked to a personal computer via an USB-RS232 serial communication port to provide the supervisory control mode. analysis and result and the last chapter is a discussion and conclusion. 1.7 Organization of the project This project is composed of five chapters covering introduction. literature review. It's the desired output. In our block diagram representation. It is an interconnection of components connected or related in such a manner as to command. Some devices are not controllable.PLC Based Automatic Air Conditioning Control System CHAPTER TWO LITERATURE REVIEW 2.1 Control system A Control System is a device. as measured by the sensor is subtracted from the input (which is the desired output) as shown below. E. The device which performs the subtraction to compute the error. The input will usually be an ideal form of the output. 10 | P a g e . That forms an error signal that the controller can use to control. Usually. and output devices (actuators). The input devices sense what is going on in the process. or a collection of devices that manage the behavior of other devices. direct. or regulate itself or another system. controllers. the last part of this system is the controller. In other words the input is really what we want the output to be. the output. and the output devices manipulate the process to achieve the desired result. we show the output signal being fed to the sensor which produces another signal that is dependent upon the output. Every control system may be divided into three general sections: input devices (sensors). the controller decides what to do about it. Finally. And is an interconnection of components forming a system configuration that will provide a desired system response. is a comparator. 1 control of temperature Thus. counting.2 Introduction to Programmable Logic Controller “PLC” Before PLCs came into existence. the controller has two things that it has to achieve: To compute what the control error should be. Serial communication is used between a PC and the PLC to download and upload programs to and from each other. and data handling. 2. sequencing. timers.4 Basic parts of PLC:Basic parts of the PLC are as follows: Processor Memory Input/output devices Programming panel or unit 11 | P a g e . A PLC is a very useful decision-making device in industrial applications.PLC Based Automatic Air Conditioning Control System Figure 2. timing.3 The Role of the Programmable Logic Controllers (PLC) A Programmable Logic Controller (PLC) is a specialized computer used for the control and operation of manufacturing process and machinery. 2. sequencing. and dedicated closed-loop Controllers. and Other controls were accomplished using physical relays. It uses a programmable memory to store instructions and execute functions including on/off control. arithmetic. safety interlock logic for manufacturing. 2. To apply the computed control effort. 4.2 Basic structure of PLC 2. Central processing unit (CPU) performs the following tasks:- Scanning Execution of program Peripheral and external device communication Self.1 Processors module:Processor module is the brain of the PLC. 12 | P a g e . Permanent storage for the operating system and the fixed data used by the CPU and Random Access Memory (RAM).PLC Based Automatic Air Conditioning Control System Power supply Figure 2.2 Memory The memory of a PLC basically consists of Read Only Memory (ROM) . stores data/information on the status of input and output devices and the values of timers and counters and other internal devices.diagnostic 2.4. 4. Figure 2. some example of input modules are limit-switches. 2. Usually. have electrically isolation between the load being connected and the PLC.3 Input modules There are many types of input modules to choose from. 2. relays.5 A programming unit Is necessary to create the user-program and send it to a PLC CPU module's memory. It is an external. although power supply modules are available for other input power characteristics.4.4 Output modules:Output modules can be used for devices such as solenoids. Namely: Low/high frequency Analog/digital (two-bit. Power supply modules may be connected to the bus or may have to be wired to the CPU module in modular PLC systems.6 The power supply A power supply module converts available power to dc power at the level(s) required by the CPU and I/O module internal circuitry. multi-bit) Maintained or momentary 5V/24V/110V/220V switched 2. like input cards. Output power must drive the computer circuitry at 5 V dc.PLC Based Automatic Air Conditioning Control System 2. nature of input classification can be done in three ways. pilot lamps and led readouts. The type of input module selection depends upon the process. the available power is typically 60 Hz/120 V ac or 50 Hz/220 V ac. Output cards. contractors. Output cards usually have 6 to 32 output points on a single module. proximity switches and push buttons etc. electronic handheld device which can be connected to the processors of the PLC when programming changes are required.4.4.3 power supplies in a PLC system 13 | P a g e . PLC Based Automatic Air Conditioning Control System 2. and optionally for RS 485. PLCs usually built in communication ports for at least RS232. This sequential processing is called cyclic operation.1Cyclic operation A PLC program is sequentially executed from the first step to the last step. and Ethernet.7.6 Characteristic Functions of a PLC It is field programmable by the user It contains programmed functions It scans memory and inputs and outputs (I/O) in deterministic manner It provides error checking and diagnostics It is packaged appropriately It has general purpose suitability 2. Cyclic operation of the PLC continues as long as conditions do not change for interrupt processing during program execution. 14 | P a g e . or even with another PLC.7 Processing Methods 2. which is called scan.5 Communications in PLC There are several methods how a PLC can communicate with the programmer. 2. 1 Programming languages A program consists of one or more instructions that accomplish a task. ”. Apple Logo. 2. LOGO Soft Comfort provides two options of creating circuit programs: ●Ladder diagram (LAD) ●Function block diagram (FBD) 15 | P a g e .8. Harold Abelson. Programming a PLC is simply constructing a set of instructions.8 LOGO Logo is the name for a philosophy of education and a continually evolving family of programming languages that aid in its realization.PLC Based Automatic Air Conditioning Control System 2. 1982. Memory cartridge 8. Expansion terminal power supply 4. LCD screen (multi characters) 9. right.5 the Siemens LOGO! PLC 1. Visualization LED RUN/STOP 3. Connection terminal for outputs 16 | P a g e . down. Keypad with 6 keys (arrows: up. left and ESC and OK keys) 6.PLC Based Automatic Air Conditioning Control System Figure 2. Connection terminal for outputs 2. PLC connection lever 10. Connection terminal for inputs 5. Connection terminal for inputs 7. Most components functions can be categorized into 4 categories: Input Output Control Communication system 17 | P a g e . Each of these components can perform their function. problem and other related issues. which are all part of the complete system.PLC Based Automatic Air Conditioning Control System CHAPTER THREE METHDOLOGY There are few stages that will be involved in order to work out the aimed objectives in this project. the finding is done doing some literature review. After finding write objectives. The project is divided in to two parts which are hardware and software development. The project was beginning by discussion the project with our advisor. The software we used is programmable logic controller using ladder logic programming.1 PLC based control system Automatic air conditioning systems commonly consists of several components. After that the project development is begin. The overall block diagram below shows the connection of PLC with its input sensors and outputs Figure 3. PLC Based Automatic Air Conditioning Control System Figure 3. Some example of sensors: humidity / pressure sensor Light sensor (photodiode. thermostat ) Heat sensor Flow sensor o Fluids (flow meter. such as a PLC. Sensors are connected to the input of a PLC.1 Input Functions Input functions are mostly performed by components called sensors. resistance thermometer. thermocouple.2 Block diagram 3. 100. photo resistor ) Temperature sensor (pt. mass flow meter ) o Electricity meter 18 | P a g e . Sensors are devices that convert a physical condition into an electrical signal for use by a controller. driving a compressor. 3. fan or blower. including but not limited to: Setting an output after a timer has reached a certain state Setting an output after a logical combination of inputs has occurred Setting a diversity of outputs after an input occurs 19 | P a g e . To get an actuator to do something useful in an automatic air conditioning system. most of the time it has to be equipped with extra mechanical/electric systems. Electric motors are used at home (mixer. rotating a pump impeller. This mechanical energy is used for.PLC Based Automatic Air Conditioning Control System 3. An electric motor is an electromechanical device that converts electrical energy to mechanical energy. lifting materials etc. drill. and fan) and in industry.3 Control functions Control functions are somewhat different than input/output functions in that their functionality itself is not so easy to describe. Electrical motors are used for powering of different pups and fans. It also can be used to apply a force. Control functions can be a lot of things.2 Output functions Output functions are mostly performed by components called actuators. Some examples of actuators: Electro-mechanical switches ( relays ) Electronic controllers: o Power switches o Motor controllers Mechanical actuators: o Motor o Pneumatic actuator o Linear actuator An actuator is something that converts energy into motion. a complete system of heating. system.6 Air conditioning system An air conditioner is a home appliance.4 Design of system Here we have two system designing method.5 Hard-ware design of measuring systems The hardware development of our project is expressed using the following flow chart. or provide heat to an area.PLC Based Automatic Air Conditioning Control System Contacting an external service when an input occurs 3. or mechanism designed to dehumidify and extract heat from an area. Those are: Hard-ware design & soft-ware design 3. ventilation. and 20 | P a g e . Hardware development Figure 3.3 physical part of air conditioning system 3. In construction. The cooling is done using a simple refrigeration cycle. air cooled condenser. Proper selecting of layout of Boolean circuit and preparing PLC programming for our system 3. signal conditioning. D/A as well as display element. Selecting of proper application area of air conditioning control to our specific design.PLC Based Automatic Air Conditioning Control System air conditioning is referred to as "HVAC. 21 | P a g e . The fan draws in air from outside and circulates it over the condenser to cool it. In our project design the following main things will be included. The refrigerant absorbs heat from the evaporator and rejects it to the condenser.4 schematic diagram of air conditioning system An air conditioning system consists of different interconnected components that each has an impact on the behavior of the system and ability of the system to affect the behavior. Modeling of our system.1 Components of an air conditioner with their application Figure 3. evaporator. in a building or an automobile. Schematic flow diagram for our system.6. The fan also draws in outside air through the compressor compartment for ventilation of the conditioned space. expansion valve." Its purpose. The basic components of a room air conditioner unit are the compressor. is to provide comfort way of life during either hot or cold weather. A/D. Selecting of proper measurement elements like sensors. two motor and air filter as shown in Figure the above. Affects control performance. goes over the cooling coils and comes back into the room through the air filter.PLC Based Automatic Air Conditioning Control System The amount of ventilating air is controlled by a damper position in its path. They respond to a signal from a controller. Sensors. To drive the pumps which supply cold and warm water to the duct. A propeller converts torque from the motor to increase static pressure across the fan rotor and to increase the kinetic energy of the air particles. In understanding the steady state behavior of the system. Usually the compressor is in the outdoor portion of an air conditioning or heat pump system. All the components are listed below with their operation. electric motors are used (stepper motors). Actuator: Actuators drive valves and dampers to open or closed positions. Mostly. Heat exchanger-are most important. Fans: can be thought of as low pressure air pumps that utilize power from a motor to output a volumetric flow of air at a given pressure. Heat pump compressor: Which compresses low pressure refrigerant gas into a high pressure. high temperature gas. The room air enters the evaporator chamber. Gives response time. Since affect the gain of the process Dampers and valves: for controls the flow. To pump the water with in the chiller and boiler. There are three main types commonly used in HVAC control: Modulate the flow through dampers and dampers. Pumps-are used. 22 | P a g e . 2 Air conditioner controls and features. 3. In the indoor the refrigerant becomes liquid and gives off heat when it is compressed. 3. Warm room air is drawn through the filter. and which takes air from the occupied space and returns it to the cooling system air handler. then blow it over cooling coils and back in to the room. condensate handling system. Which include a room thermostat. electrical switches. This state change of the refrigerant. The key elements of the air conditioner are a refrigerant that flows constantly through its mechanisms. cooling the evaporator coil surface and thus cooling indoor air blown across the cooling coil.6. The heat removed is discharged outdoors. and air filters. An air handler and blower unit: This provides a fan to blow building air across or through the evaporator coil. and over which a fan blows air to cool the refrigerant gas back to a liquid state (thus transferring heat from the refrigerant gas to the air being blown by the fan).PLC Based Automatic Air Conditioning Control System Supply of conditioned air to the room A condenser: or condensing unit: typically a condensing coil inside which high temperature high pressure refrigerant gas flows. An evaporator coil or cooling coil: Typically the cooling coil is a section of finned tubing (it looks like a car radiator) into which liquid refrigerant is metered and permitted to evaporate from liquid to gas state inside the coil. which removes dust and lint 23 | P a g e . absorbs heat.3 Operation principle Air conditioners take in warm room air. from liquid to gas.6. fuses or circuit breakers. Electronic sensing is done by using low mass primary elements that respond quickly to changes in the controlled condition.it becomes a gas and absorbs heat when the pressure is removed. The air handler blower fan unit moves building air across the evaporator coil surface in order to condition building air by cooling it (and thus also by removing moisture from the cooled air A duct system: Which distributes conditioned air from the air handler in to the occupied space (supply ducts). The mixed air is supplied to the room through the heater or cooler duct to perform the required set temperature by the help of supplied fan. The refrigerant is returned to the cooling coil as a liquid. 24 | P a g e . The fan blows the air over the cooling coils containing the refrigerant fluid. and in the process.PLC Based Automatic Air Conditioning Control System particles. The outdoor air come from the atmosphere pass through the damper and the return air mixed with outdoor air in the damper according to the signal from the temperature sensor. The temperature set up happened according to the controlled program with combination with the sensor response action as well as the signal conditioning element which all be listed below latter briefly. The vaporized refrigerant moves to the compressor. Here its heat is transferred by the fan to the outside. Therefore the automatic control activity of controlling the temperature will continue through these combinations of all elements. causes the refrigerant fluid to vaporize. which pumps it under pressure to the condenser coils. The basic purpose of the design is to control temperature flow through the room automatically. Steps of operation that system operates as follows. The warm airs gives up its heat to the refrigerant. PLC Based Automatic Air Conditioning Control System Figure 3. Since the birth of home and building automation systems.5 Interfacing of hardware and software components of logo PLC control 3. a multitude of standards has popped up. For example: Simple copper wiring (elder days) Telephone line Parallel communication Serial communication 25 | P a g e . there is a need for a communication system between all these components.6.4 Communication Evidently. our project uses to transmit data from PC to PLC the serial communication. referred to as a PC/PPI cable. 30 m at 9600 baud. including DB-9 and DB-37. is needed when a personal computer is used as a programming device. Has a maximum effective distance of approx. with the majority of computer hardware and peripherals. 3. RS-422 is a Standard interfaces approved by the EIA. RS-232 is a standard interface approved by the Electronic Industries Association (EIA) for connecting serial devices. and the standard specifies up to 32 drivers and 32 receivers on a single (2-wire) bus Programming Device Cable: A special cable. This cable allows the serial interface of the PLC to communicate with the RS-232 serial interface of a personal computer. RS-485 is an EIA standard for multipoint communications. RS-485 is similar to RS-422 but can support more nodes per line RS-485 meets the requirements for a truly multi-point communications network. It supports several types of connectors.7 Software development The concept of controlling a control system is very simple and easy task it involves systematic approach 26 | P a g e . Common Standards RS -232 Used in short-distance computer communications. and designed for greater distances and higher Baud rates than RS-232.PLC Based Automatic Air Conditioning Control System Coax Infrared Twisted pair cable Fiber optics Wireless From the communication equipment above. We limited our selection to the thermal sensor.2 Temperature sensor LM35 Description 27 | P a g e . Programming into Memory: 5.8. pressure sensor 6. Assignment of Inputs and outputs: 3.8. 1. A room containing an extractor fan & fresh air fan Each fan is monitored by means of flow sensor Humidity Light of the home 3. Writing of the program: 4. Photo sensor 4. motion detector In this project the type of sensors that we have selected is temperature sensor which is a thermistor type of LM-35 which is a variable temperature sensor. Temperature sensor.1 Sensor Selection Sensor is used to produce a varying signal according to the quantity being measured.1 Programming structure Requirement for air conditioning system An air conditioning supplies fresh air into a room industry& exhausts contaminated air.8 Proper selection of sensors and signal conditioning element 3. Determine the system sequence of operation: 2. humidity 5. 3.7. Heat detector 3.PLC Based Automatic Air Conditioning Control System By the following operation procedure 1. 2. Running the system: 3. PLC Based Automatic Air Conditioning Control System For our design purpose we select the temperature sensor LM35 as a sensor which has the following criteria. Integrated circuit temperature sensors whose output voltage is linearly proportional to the Celsius temperature.6 LM35 sensors. Easy to use and adaptable. 3. Are inexpensive. The temperature sensor that is used is LM 35 sensor which is type of thermistor.4 Humidity sensor A system that is sensed by humidity sensor. Humidity refers to the amount of wetness or water vapor in the soil.8. Easily obtainable. whose electrical characteristics changes according to the amount of humidity. The most common type of humidity sensor uses what is called “capacitive measurement. Are temperature sensitive resistors. This is also suitable for remote applications. The LM 35 series are. Can have reasonable output voltages. Figure 3.” 28 | P a g e . Previous solution The fans are monitored with air flow monitors. An indicator light is intended to indicate failure of a fan.1 HVAC control system To monitor the temperature. The evaluation circuit can be replaced by one single LOGO. photo. this can be acknowledged by pressing the off button. The fresh air fan may only be switched on when safe operation of the exhaust air fan is signaled by the air flow monitor. At no time should the room become pressurized. The thermostat senses the signal of the temperature from the environment and converts this temperature signal to voltage signal and compared with the setting value. Based on this result we have the following result. 4.2 Requirements for Air conditioning A ventilation system is intended to supply fresh air to a room.PLC Based Automatic Air Conditioning Control System CHAPTER FOUR RESULTS & DISCUSSION 4. motion. in addition to the air flow monitors. and extract the used air. LOGO! Solution Fan monitoring requires an evaluation circuit and several switching devices. humidity sensors and their respective out puts. Each of the two fans is monitored by an air fault monitor. 29 | P a g e . When no air flow is measured after a short delay has elapsed. the system is switched off and a fault is reported. humidity. light of the room we need different sensors typically thermostat LM_35A fault sensor. (Q2&Q3 will be on at the same time for few seconds ) If the setting value is greater than the record value then the room is in a cool condition so that the fault sensor sends the signal to the fault indicator at the same time hot air fan starts to hot the room to become normal. Figure 4.( Q2&Q4 will be on at the same time for a few seconds) 4.(Q1 will be on for a second) If the setting value is less than the record value then the room is in a hot condition so that the fault sensor sends he signal to the fault indicator at the same time cool air fan starts to cool the room.2 LOGO! Wiring Figure 4.1 previous solution No Symbol Comment 30 | P a g e . This allows a saving to be made in installation time and space in the control cabinet.3 Connection of PLC Fewer components are required than for the conventional solution.PLC Based Automatic Air Conditioning Control System If the setting value is equal to the record value then room is in normal condition. 1 air conditioning input and output 31 | P a g e .PLC Based Automatic Air Conditioning Control System 1 2 3 4 5 6 7 8 9 10 11 12 13 14 I1 I3 T002 T002 T005 T005 T007 T007 T008 T008 Q1 Q2 Q3 Q4 Temperature sensor Fault sensor Auxiliary timer Q1 On and off timer Q1 Auxiliary timer Q2 On and off timer Q2 Auxiliary timer Q3 On and off timer Q3 Auxiliary timer Q4 On and off timer Q4 Normal air condition Fault displayer Cooler air fan Heater air fan TABLE 4. PLC Based Automatic Air Conditioning Control System Figure 1 Ladder diagram of air conditioning 32 | P a g e . I2 and I3 lamp Q1 and Q2 is on until the timer setting is finish its counting after it the lamp Q3 is on. Until the timer B007 is stop its counting after it the Q3 is on. And when we on the I1.PLC Based Automatic Air Conditioning Control System Figure 2 Air conditioning in FBD The I1 is the off and the I2 is on. When we give an input I1 and I2 the lamp one is on (Q1)which means the exhaust air fan starts its function. 33 | P a g e . PLC Based Automatic Air Conditioning Control System 4.4 Air Conditioning 34 | P a g e . PLC Based Automatic Air Conditioning Control System 35 | P a g e . PLC Based Automatic Air Conditioning Control System Figure 3 Ladder diagram of air conditioning 36 | P a g e . PLC Based Automatic Air Conditioning Control System Figure 4 Air conditioning in FBD 4. The input & output assignment can be as follows: 37 | P a g e .5 Humidity control system Here we have only one input that is moisture sensor and one output (pump motor). PLC Based Automatic Air Conditioning Control System No 1 2 3 4 Symbol I2 Q5 T001 T001 Comment humidity sensor Pump air Timer coil auxiliary Contact point of timer Table 4. 38 | P a g e .2 humidity control system Figure 5 Ladder diagram of humidity Figure 6 Humidity in FBD The I1 is lighting sensor which senses the light and darkens. Those are in their function. If we give a power the timer is starts counting and the output which is the Q1 and Q2 is on. PLC Based Automatic Air Conditioning Control System 39 | P a g e . PLC Based Automatic Air Conditioning Control System 40 | P a g e . 6 Lighting control system We select two inputs for automatically on the light of the home. Those are lighting dependent sensor and occupancy/ motion sensor. 41 | P a g e .PLC Based Automatic Air Conditioning Control System Figure 7 Ladder diagram of the overall air conditioning system 4. 3 lighting control system 42 | P a g e .PLC Based Automatic Air Conditioning Control System No Symbol Comment 1 I1 Photo sensor 2 I2 motion sensor 3 I3 motion sensor 4 I4 motion sensor 5 I5 motion sensor 6 I6 Alarm contact 7 Q1 Exterior lighting 1 8 Q2 Exterior lighting 2 9 Q3 Exterior lighting 3 10 Q4 Interior lighting Table 4. PLC Based Automatic Air Conditioning Control System 43 | P a g e . PLC Based Automatic Air Conditioning Control System Figure 8 Ladder diagram of light controling Figure 9 FBD of light control 44 | P a g e . after switching off the exterior lighting. and Q3). The exterior lighting is also switched on via the alarm contact of the alarm system at I6 for 90 seconds. LOGO! Solution The exterior lighting is divided into three areas (at Q1. A fourth motion detector is connected at I5. 45 | P a g e . persons approaching are to be detected and the exterior and interior lighting switched on via motion detectors and the alarm contact of an alarm system. I3. (5:00 in the evening to 7:00 in the morning). Via the motion detector at I5 and the alarm contact the internal lighting is immediately switched on for 90 seconds. The photo-sensitive switch at I1 guarantees that the lighting is only switched on when it is dark. Each area has its own motion detector (at I2.PLC Based Automatic Air Conditioning Control System Requirements The exterior and interior lighting of a house is controlled using LOGO. which independent of time and darkness switches on all exterior lighting for 90 seconds. The time period is set via a time switch integrated in LOGO. In addition. In the absence of the occupants and when it is dark. and I4). If one of these motion detectors is activated during a certain period the corresponding exterior lighting is switched on. the interior lighting is switched on for 90 seconds. Q2. 1 Project Conclusion To conclude. 46 | P a g e . there is no need of switches. in automatic air conditioning system temperature is an important parameter to control system to keep the room industrial at the state of comfort for human being. So. voltage comparator. In the case of the humidity we have got only one humidity sensor.PLC Based Automatic Air Conditioning Control System CHUPTER FIVE CONSLUSION AND RECOMMENDATION 5. This consists of measurement system like thermistor which is used to record the variation of temperature of the surrounding then this recorded temperature is compared with the set value or desire value of the room so that error signal is send to the PLC but before reaching the PLC various devices are used to amplify the signal of the thermistor. PLC controller and all the system works automatically. And other parameters that we have made controlled are the humidity. the light system. The light system is controlled using the photo sensor which is used to sense the presence of light or darkness so that if there is darkness the light will be on for the person who comes to the room which is sensed by the motion sensor which is send a signal a movement of the person to the photo sensor so that the photo sensor will be make the light on or off. becomes humidify or dehumidify according the customer want. which is used to sense the humidity of the environment and it. 2 Recommendation Although the proposed controller is quite complex. there are additional improvements that can be made to obtain a more robust system: for example Oder of the environment checking mechanism is not taken in to consideration so that it is better for engineers to do this mechanism of checking as a result of this the people may live in a comfortable way even if the air is disturbed with a bad Oder of the environment and we have no included the alarm system which is useful for any variation of signal to send a signal of the sound to the person.PLC Based Automatic Air Conditioning Control System 5. 47 | P a g e . 1374 1379 6. 1970. M. C. pp. C. 8. 2009. P. Calvino. 2009 48 | P a g e . 2004. Zhijian Hou. pp. S. pp. 1992 9. Telerobotics. Chiou. Henry Nasution. Gennusa.9.PLC Based Automatic Air Conditioning Control System REFERENCES 1. Chu. Meng Qinglin. pp. McGraw-Hill New York. Thermal Comfort of Natural Ventilated Houses in Countryside of Subtropical Region 2011. 139-150 3. 4. Chen Cunen.97-102. Yuji Yamakawa. Shafizal Maarof. Fanger.310316 2.B. G. 2008.1. The application of fuzzy control on energy saving for multi-unit room air-conditioners. Takanori Yamazaki. Analysis and Applications in Environmental 7. Scaccianoce. Thermal Comfort Factor in Hot & Humid Region: Malaysia.H. F. Zeng Junjie. 2011. Philip Jones Prof.Vol 36. Shigeru Kurosu. Automation and Human Supervisory Control. Jin Ling. pp. Zhiwei Lian (2009) Application of Temperature Fuzzy PI Controller Based on PLC. TELKOMNIKA. No.L.4 5. G. Applied Thermal Engineering. Jamaluddin Mohd. Kazuyuki Kamimura. Thomas B. Energy Analysis for Air Conditioning System Using Fuzzy Logic Controller. 6371-6375 10. pp. Lin.Chiou. Energy and Buildings. Compensation of manual reset to offset thermal loads change for air-conditioning system.M. Hishamuddin Jamaluddin. Rizzo. Sheridan. Engineering. 1 . C. Vol.O. The control of indoor thermal comfort conditions: introducing a fuzzy adaptive controller".L. Thermal Comfort. 2009. Central Processing Unit PID ……………………………………………………Proportional Integral Derivative PG 702…………………………………………………Programming 702 49 | P a g e . ventilation.point to point interface DIP…………………………………………………… Data information process LAN ………………………………………………… Local Area Network CPU …………………………………………………. air-conditioning PC…………………………………………………… personal computers LDR ………………………………………………… Light dependent resistor EIA ………………………………………………… Electronics Industry Association PPI…………………………………………………….PLC Based Automatic Air Conditioning Control System APPENDICES ABBRIVETIONS PLC………………………………………………… programmable logic controller RS-232 ……………………………………………… Recommended standard 232 RS-485……………………………………………… Recommended standard485 HVAC……………………………………………… heating.