Automatic Controls for Any Process

Chapter 5Automatic ControlsAutomation plays a authentically critical function in the development and promotion of whatsoever carcass. Automatic fitler refers to the get wind of any procedure, twisting or a placement utilizing unbidden agencies instead than manual(a) visit. Automation a body is done to better the creation debut and to increase the increaseiveness of the transcription. Automatic ensure has become an built-in specify in every field whether it is industry, robotics, vehicles, power belongss, etc. to increase the productiveness, public introduction and efficiency of the system control systems ar employ to fill the mechanization. Control system fundamentally refers to the interconnectedness of the constituents to configure the system to app closure forth the envy end product.5.1 Types of Control SystemThere be fundamentally both fonts of control systems bode 5.1 prefatory types of Control systemsClosed cringle system is good than unfastened cring le system. The control system enforce for this childbed is a closed cringle electronic control unit which arsehole command the end product of the system.5.2 Components of Control systemThere argon assorted constituents of control system that includes the procedure whose end product is to be controlled, infos encyclopaedism unit, electronic control unit and end product devices.5.2.1 ProcedureIt is the basic constituent of the control system as this is the constituent whose end product is to be controlled utilizing the automatic control. So it is required to mathematically pattern the procedure to understand the carriage of the stimulation and so act as forth the desired and controlled end product ( Mutambara Arthur 1999 ) .Top of FormBottom of Form5.2.2 Data Acquisition UnitIt is that unit of the system that fag end mensurate galvanising or natural measure in the pattern of electromotive force, current, temperature, sound, etc. It by and large measures the pair signal an d so treat it utilizing signal instruct or pair to digital convertor. The physiologic information from the detectors is send to the cardinal unit to be processed. PIC16f73 littlecontroller is use as the nucleus of DAU and it performs the repeat to digital alteration and so sends the processed end product signal to the end product device. PIC microcontroller is chosen as it provides the necessary functionalities mandatory to the substance abuser. Besides it has utmost velocity parallel to digital rebirth ability. PIC microcontroller is farther connected to liquid crystal disposition ( LCD ) , doorbell and a motor to expose the end product.Basic constituents of DAQ unitFigure 5.2 Components of DAQ unit ( What is data acquisition? 2014 )Detectordetector is an input device apply to mensurate the physiological signals akin temperature, idle olfactory property, etc. It is in any event called transducer that converts a physical signal into measureable electrical signal. The elec trical end product of the detector may be in the signifier of current, electromotive force, opposition or early(a) electrical signal depending upon the type of detector used. In this undertake, intoxi so-and-sot detector and eye-blink detectors argon used which ar already discussed in the old chapter 3 and 4.DAQ DeviceIt is the interface among the input signal from the detector and the figure shape. It is fundamentally used to substitute over the linear signal coming from the detector into a digital signal which stick out be tripping interpreted by the computation machine. Its chief map is to mensurate the parallel signal utilizing signal conditioning and so change over it into digital signifier. For this project the microcontroller go away choke as a DAQ device and it will work on the operating instructions programmed in its computer storage. Microcontroller used in this undertaking has inbuilt parallel to digital convertor so at that place is no demand to link parall el to digital convertor externally.Computer SystemThe DAQ device is connected to the figuring machine utilizing a port. The calculate machine coach linking the DAQ and the computing machine system acts as a communicating nexus betwixt the computing machine and the DAQ device for go throughing the instructions and the measured informations. In this undertaking, a political program is written in programming package ( Mikro C ) and this plan is fed into the DAQ device utilizing a microcontroller burner and a coach. This connexion between the DAQ device and computing machine is made simply for infixing the codification into it. After that there is no demand for computing machine, the device will execute its maps on its ain ( What is data acquisition? 2014 ) .5.2.3 electronic Control unitThe electronic control unit ( ECU ) controls the fuel system, ignition system and velocity of the engine. It chiefly consists of microprocessors or microcontrollers, random entree entrepot ( hale ) , read nevertheless memory ( ROM ) and input end product devices. Based on the information from the input detectors, the ECU determines the end product of the electronics circuit. It is considered as the encephalon of the control system as its work is to take the signal and bring forth the mechanically controlled signal required by the end product. Microcontroller serves both the intent of informations acquisition and commanding the end products of the undertaking ( Vincent T, Ciulla 2002 ) .5.2.4 Output ActuatorIt is besides known as end product device that converts the electrical signal into some physical end product. It receives the controlled signal from the electronic control unit in the signifier of electrical signal. It is the device which influences the procedure of the system physically and forces the device to bring forth the coveted end product. The actuator applicable to this undertaking is motor that is used to bespeak the end product of the system.This undertaking b esides requires a control unit as the vehicle is automatically controlled in this system.5.3 Types of electronic controlThree types of electronic controls are used majorly in any system Figure 5.3 Types of Electronic ControlsComparison between different types of controls is devoted in the following tabular array base upon their characteristics and public presentation. This comparing is draw to find the go around suited type of control to be used in this undertaking. hold over 5.1 Comparison between different types of controlsMicroprocessorMicrocontrollerProgrammable Logic ControlA microprocessor works as a Central Processing Unit of a general intent computing machine.It can be considered as micro computing machine as all the constituents are embedded on a individual bit.It is a specialised system designed to command the industrial procedures and machinery.I/O ports, memory, timers, interrupts, etc are non inbuilt so they are connected externally.Microcontroller has all the exces s peripherals deal I/O ports, memory, timers, counters, interrupts, etc are built-in inside the bit merely.It has a programmable memory to hive away specific maps like on/ forward control, timers, counters, arithmetic and informations handling. It has limited figure of inputs and end products.Microprocessors establish systems are gigantic and rightfully practically expensive as it gives rattling high bear upon velocity.These are easy available and are less(prenominal) bulky and much cheaper than microprocessors.PLCs are usage programmed for merely peculiar undertakings so their hardware is truly dearly-won and need regular care.But its drawback is that it has really some pins that are programmable.Most of the pins of microcontroller are programmable.It is a programmable logic control and uses ladder logic for scheduling.It can merely manage a a couple of(prenominal) spot of instructions as it has really less built-in memory.It has inbuilt memory so it has many spots to man age instructions.It has really small memory which can manage few instructions.It is widely used in desktop computing machines and laptop, notepads, etc due to its high processing velocity.It has moderate processing velocity so it is widely used in little control systems, contraptions like oven, telecastings, etc.It is by and large used for industrial applications for automatic control of industrial machinery, procedure etc.Slightly macro surface due to excess peripherals and operates above 1Ghz.Small in size and operates from really few MHzs to 30-50 Mhz.Its size varies from little, medium to really big PLC panels.Examples of microprocessors are 8085, 8086, INTEL Pentium series, etc.Examples of microcontrollers are INTEL8051, PIC16f73, PIC16F877, etc.Examples of PLC are industrial control, industrial safety applications, etc.The research worker heady to utilize the microcontroller bit for the processing of detected signals because it is little in size, cheap and consumes less pow er. It does non necessitate any external input/ end product ports, memory, timers or interrupts as it has all these characteristics inbuilt in its internal architecture. Higher compound of microcontroller besides reduces the cost and size of the system which serves the basic demand of the user every bit good as the research worker. PLC based systems are really much expensive to be used for this intent ( fundamentals of microcontrollers 2011 ) .5.3.1 Choice of microcontroller for the undertakingAfter make up ones fountainheading the microcontroller it is of import to make up ones mind which microcontroller should be used in this peculiar undertaking that can vanquish suit the demands of the undertaking. For this intent a comparing between different types of microcontroller is drawn in the undermentioned tabular array.Table 5.2 Comparison of Different MicrocontrollersPropertiesPIC microcontrollerMicrocontroller 8051AVRDirection SetIt is based on reduced instruction set computer ( trim delegacy set calculation ) . It has merely 35 set of instructions that makes its architecture easy to larn.It is based on CISC ( Complex direction set calculation ) . It has a big figure of instructions about 250 instructions.It is besides based on RISC ( Reduced direction set calculation ) but it has big direction set i.e. non-orthogonal. It has about 140 instructions.Processing SpeedIt can treat 3 trillion instructions per second because in 1 machine rhythm of PIC, quantify frequence is divided by 4.It can treat 1 one trillion million million instructions per second because in 1 machine rhythm of 8051, quantify frequence is divided by 12.It can treat 12 million instructions per second because in 1 machine rhythm of AVR, clock frequence is divided by 1.ADCIts velocity of parallel to digital transition is really fast than AVRs.It does non hold inbuilt parallel to digital convertors like PIC and AVR.Its parallel to digital transition velocity is slower than PIC.Power inge stionIt has least power ingestion.It consumes the most power out of all the three microcontrollers.It consumer higher(prenominal) power than PIC microcontroller.ProgramingIt is really easy programmable IC as it really easy to code.Cryptography of microcontroller 8051 is besides easy.It has really complex cryptography for novices as compared to other two microcontrollers.MemoryIt has 8k bum memory, 368?8 byte RAM.It has 256 byte internal RAM and 4k on-chip ROM.It has 8k byte flash memory, 1k byte RAM.Cost and AvailabilityIt is easy available in market and that excessively at low cost.It is besides low lost and easy available.It is dearly-won as compared to 8051 and PIC micro accountant and handiness is besides limited.As detectors are used in this undertaking so it is better to utilize a microcontroller with built-in ADC with fast transition velocity alternatively of utilizing separate ADC after every detection faculty. By maintaining this in head the research worker had studied the characteristics of assorted microcontrollers which can be used to devour the stroke bar system and in conclusion reached to the decision of utilizing PIC ( Peripheral Interface Controller ) microcontroller.Researcher decided to utilize PIC16f73 is used in the undertaking due to its high parallel to digital transition. The pin architecture of PIC16f73 is given figure 5.4.5.4 Architecture of PIC16f73 microcontrollerFigure 5.4 Architecture of microcontroller PIC16f73 ( Microchip 2002 )It is a 28 pin IC and the coveted undertaking can be made utilizing 28 pins with 3 input end product ports. It has 192 byte RAM ( Random Access Memory ) and it is based on RISC architecture with merely 35 set of instructions. It has 8k brassy memory, 4k programmable memory and 368?8 byte RAM. It has 3 ports viz. port A, B and C. port A consists of 5 parallel to digital channels for ADC transition. Assorted parametric quantities for choosing PIC16f73 microcontroller are listed below.PerformancePIC16f7 3 microcontroller which will be used in the execution of this undertaking is a 28 pin IC with 3 input-output ports. It besides has 192 bytes of RAM ( Random Access Memory ) and is based on RISC ( Reduced Instruction Set Computation ) architecture for better public presentation of the Accident Prevention System. It has much faster transition velocity of parallel to digital transition than other accountants.Power ingestionA PIC controlled system has minimal power ingestion with good public presentation which is needed by the accident bar system. So this characteristic of PIC is really utile for the system being developed as the system would work on minimum power without compromising the system public presentation.MemoryThe accident bar system utilizing intoxicant and oculus winking sensing can be done utilizing the built-in memory of PIC but mum if the demand of memory of the system increases. PIC microcontroller besides has 4k programmable brassy memory and most of the PIC based sys tems are memory expandible and can spread out its memory as per use and type of application. To implement this system its built-in memory is adequate ( Bates Martin, 2011 ) .Therefore from this chapter, the control unit used for this undertaking is finalized. This chapter gives a brief overview of assorted control devices. Comparison between different control systems is drawn. The justification for taking a peculiar control unit is besides given. The short account of microcontroller used is besides given in this chapter.Now all the basic constituents to be used in the undertaking are decided. Therefore from the following chapter, design of circuitry and the system will be done. After that this system should be implemented and so tested.