BAKISS HIYANA ABU BAKAR COURSE LEARNING OUTCOMES CLO Explain clearly blocks parts components and instructions found in the automation systems C3 Construct simple automation sequential control of hardware or PLC system based on IEC 61131 and NEMA standards C4 ID: 1029754
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1. CHAPTER 3INTRODUCTION TO PLC SYSTEMBAKISS HIYANA ABU BAKAR
2. COURSE LEARNING OUTCOMES (CLO)Explain clearly blocks, parts, components and instructions found in the automation systems. (C3)Construct simple automation sequential control of hardware or PLC system based on IEC 61131 and NEMA standards. (C4)
3. Objective :Understand basic characteristics of PLCPLC terminologiesPLC function/ backgroundType / advantages of PLCUnderstand building structure of PLCCPU, memory unit, display and indicator unit, input and output interfaceUnderstand PLC hardware unit Housing unit, programming unit, power supply unit, printer unitExplain input and output device
4. A digital device (microprocessor based controller) that uses a programmable memory to store instructions and to implement functions such as logic, sequencing, timing, counting and arithmetic in order to control machines and processes and has been specifically designed to make programming easy.PLCs are similar to computers but have certain features which are specific to their use as controllers: i. They are rugged and designed to withstand vibrations, temperature, humidity and noise. ii. The interfacing for inputs and outputs is inside the controller. iii. There are easily programmed.Introduction PLC (Programmable Logic Control)
5. 3.1.1 Define PLCWhat is Programmable Logic Controller (PLC) ? Definition: National Electrical Manufacturers Association US (NEMA) A PLC is a digital operating electronic apparatus which uses a programmable memory for internal storage of instruction for implementing specific function such as logic, sequencing, timing, counting and arithmetic to control through analog or digital input/output modules various types of machines or process.
6. An electronic system working digitally for the use in industrial environment with a programmable memory for the internal storage of user-orientated control instructions for the implementation of specific functions. For example: logic operation control, process control, timer, counting-and arithmetic functions, in order to control various machines and processes through digital or analog input , and output variables. The logic programmable controls as well as the peripheral installations (PLC-system) are designed so that they can be easily integrated in an industrial control system and be implemented in all their desired functions. - International Standard IEC 61131-13.1.1 Define PLC
7. 3.1.1 Define PLCSeveral different terms used to described programmable controllers: i. PLC –Programmable Logic Controller (UK origin) ii. PC – Programmable controller (US origin)Most referring to the functional operation of the machine.PLC has been used in this text to avoid confusion with the personal computer.**Before the 1980’s, programmable controllers were called PCs.
8. 3.1.2 PLC Background PLC Development factors:Needs for low-cost FlexibleEasily commissioned/ smart usage
9. 3.1.2 PLC Historical Background: The first Programmable Logic Controller (PLC) was developed by a group of engineers at General Motors in 1968 The company was looking for an alternative to replace complex relay control systems. The PLC must be: Must be programmable / Easy to program.(and reprogrammable) Designed to operate in an industrial environment Must accept 120 V ac signals from pushbuttons, switches Outputs must switch and continuously operate loads such as motors and relays of two amps ratingNot need rewiring the control system if change the program.Smaller in size, cheaper and high reliability.Simple construction and low maintenance Cost- competitive
10. PLC performs the functions of conventional relays, timers, counters.Capable of storing instructions, such as sequencing, timing, counting, arithmetic, data manipulation, and communication, to control industrial machines and processes.3.1.3 Explain PLC functions
11. 3.1.3 Explain PLC functionsCONTROL TYPE:FUNCTIONSSequence ControlConventional Relay Control Logic replacerTimers/ CounterPCB Card controller replacerAuto/Semi-auto/Manual control of machine and process.Advanced/ Sophisticated ControlArithmetic operation (+, -, × , ÷)Information HandlingAnalog Control (Temperature, Pressure )P.I.D (Proportional Integral Derivation)Servo Motor ControlStepper Motor control
12. 3.1.3 Explain PLC functionsCONTROL TYPE:FUNCTIONSSupervisory ControlProcess monitoring and alarm.Fault Diagnostic and monitoringInterfacing with Computer (RS-232C/RS 422)Printer/ ASCII InterfacingFactory Automation NetworkingLocal Area Network (LAN)Wide Area Network (WAN)Factory Automation (F.A), Flexible Manufacturing System (F.M.S) & Computer Integrated Manufacturing (C.I.M).
13. PLC Size:Small : - It covers units with up to 128 I/O’s and memories up to 2 Kbytes. - Capable of providing simple to advance levels or machine controls.Medium : - Have up to 2048 I/O’s and memories up to 32 Kbytes.Large : - The most sophisticated units of the PLC family. They have up to 8192 I/O and memories up to 750 Kbytes. - Can control individual production processes or entire plant.3.1.4 List types of PLC
14. Types of PLC Construction:Compact PLCModular PLCPLC Plug-in CardManufacturer: OMRON, Allen Bradley, Mitsubishi, NAIS, Siemens,Toshiba, Festo etc.3.1.4 List types of PLC
15. Type of PLC - compact 3.1.4 List types of PLCOmronMitsubishiZelioTECOMAT TC600 Compact PLC – MELSEC FX3U
16. Type of PLC - modular 3.1.4 List types of PLCOmron
17. Type of PLC - plug in card 3.1.4 List types of PLC
18. Shorter project implementation time.Easier modificationProject cost can be accurately calculated.Shorter training time required.Design easily changed using software ( changes and addition to specifications can be processed by software.A wide range of control applicationEasy maintenance.High ReliabilityStandardization of Controller hardware.Able to withstand Harsh plant/process environments (Operate normally under severe conditions of temperature, humidity, voltage fluctuations and noises). 3.1.5 Advantages of PLC
19. Basic PLC Structure3.2 Building Structure of PLCBasic internal structure of PLC consists essentially of :-processing unit (CPU)-memory-input/output unitsMicroprocessor/ CPU ROM RAMInputOutput Data BUS Control BusAddress BusDesign of Basic Microcomputer
20. 3.2.1 Functions and Operation of each BlockCentral Processing Unit (CPU)The CPU controls, monitors and supervises all operations within PLC.It is also caries out programmed instructions stored in the memory.An internal communications highway also known as a bus system, carries information to and from the CPU, memory and I/O units under the control of the CPU.
21. Memory Unit For storage of programs.The user’s ladder logic program, the state of I/O in the memory of PLC.The main program and the other programs necessary for the operation of PLC.The organization of the data and information in the memory is called memory map.2 types of MemoryRAMROM3.2.1 Functions and Operation of each Block
22. Memory Unit (types of memory): RAM Random Access MemoryROMRead Only Memory (read)This memory can be read from and written to.This memory can be read onlyStoring all user’s programsStoring all system’s programEntire contents will be lost if power is switched off.Memory content remain when the power is switched off.3.2.1 Functions and Operation of each Block
23. c. Display and Indicator Unit Referring to PLC standard display Internal Relay: Console’s LCD Display if user use Mnemonic Code Programming.Monitor Screen if user use software programming method.LCD DisplayMonitor Screen3.2.1 Functions and Operation of each Block
24. d. Input Interface Unit Input Unit:Function as a medium that connects the external input devices (Switch, sensor & timer)Output Unit:Function as a medium that connects the external output devices to the CPU within PLC.( Lamp, motor & solenoid )e. Output Interface Unit I/O Unit The I/O Unit is the interface unit has function to convert the input signal and output signal so that the CPU can communicate with the external apparatus like the switch, stepping motor, solenoid, sensor, etc. The I/O Unit has two type; Discrete I/O and Analog I/O.3.2.1 Functions and Operation of each Block
25. Hardware of the PLC3.3 PLC Hardware UnitsHardware of the PLC are only consist of several components; such as Power Supply Unit, CPU Unit, Memory Unit and I/O Unit. At the small PLC; Power Supply, CPU, Memory and I/O stay in the same Unit but at the big PLC; Power Supply, CPU, Memory and I/O in the separate Unit.
26. Hardware of the PLCHousing UnitProtect PLC circuit and internal componentProgramming Unit Use to process operation and system status that will be display by PLC. i. Programming Console ii. Computer iii. Video Display Unit (VDU) iv. Program Loader Unit v. Output Interface Unit3.3.1 Identify and Describe PLC Hardware Units
27. Programming UnitProgramming Console Hand-held programming devices are sometimes used to program small PLCs They are compact, inexpensive, and easy to use, but are not able to display as much logic on screen as a computer monitor It is often used on the factory floor for troubleshooting, modifying programs, and transferring programs to multiple machines
28. Programming UnitComputer A personal computer (PC) is the most commonly used programming deviceThe software allows users to create, edit, document, store and troubleshoot programsThe personal computer communications with the PLC processor via a serial or parallel data communications link
29. Hardware of the PLCc. Secondary Storage Unit This unit related to CPU where all program and information were kept.d. Power Supply Unit:Supplies DC power to the Central Processing Unit, Input Unit and Output Unit. The most PLC works with power 24 VDC or 220 VAC. The big PLC has the separate power supply and the small PLC has power supply which is one. The Power Supply is also provided by the battery back up, when happened the failure of power, automatically battery will replace the power supply to supply the CPU, so that the program of memory user do not lose. e. Printing Unit Used to print control system programming that controlled by PLC whether graphically or text.3.3.1 Identify and Describe PLC Hardware Units
30. 3.4.1 Input DevicesPLCs can receive input from either automated or manual devices. The PLC could receive data from the user via a pushbutton switch, keyboard, or similar device. Automated input could come from a variety of devices: micro switches, timers, encoders, photo sensors, and so on. Some devices, like the Limit Switch shown below, turn ON or OFF when the equipment actually makes contact with it. Other devices, like the Photoelectric Switch and Proximity Switch shown below, use other means, such as light or inductance, in order to get information about the equipment being monitored.3.4 Explain Input & Output Device
31. Input Devices3.4.1 Input DeviceLevel SWFlow SWThumbwheel SWLimit SwitchPush Button
32. 3.4.2 Output DevicesA PLC can output to a myriad of devices for use in automated control.Almost anything that you can think of could be controlled (perhaps indirectly) by a PLC. Some of the most common devices are motors, Solenoids, Servomotors, Stepping Motors, valves, switches, indicator lights, buzzers, and alarms.Some of these output devices; such as the motors, Solenoids, Servomotors, Stepping Motors, and valves; affect the controlled system directly. Others; such as the indicator lights, buzzers, and alarms; provide output to notify personnel3.4.2 Output Device
33. Output Devices3.4.2 Output DeviceMotorSolenoidLED DisplayHeater CoilLamp
34.