Krishna pp main
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The document discusses programmable logic controllers (PLCs). It provides a definition of a PLC as a digital computer designed for industrial control applications. The document outlines the history of PLCs, which were introduced in the 1960s to replace relay-based controls. It describes the major components of a common PLC, including a processor, power supply, input/output modules, and a programming device. The document discusses ladder logic as a common PLC programming language and provides an example ladder logic diagram for starting and stopping a motor. It also lists some advantages of PLCs like reliability, flexibility, and cost-effectiveness, as well as some disadvantages such as proprietary components. Applications of PLCs include robotics
Krishna pp main
- 1. PROGRAMMABLE LOGIC CONTROLLER Presented by Krishna Kumar (1316221007) 12:43:58 PM 1
- 2. CONTENTS What is PLC? History of PLC Major components of PLC Ladder logic Advantages Disadvantages Application 12:43:58 PM 2
- 3. DEFINITION OF PLC PLC is a digital computer designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. A PLC is an example of a real time system. 12:43:58 PM 3
- 4. PLC was introduced in late 1960’s First commercial & successful Programmable Logic Controllers was designed and developed by Modicon as a relay replacer for General Motors. Earlier, it was a machine with thousands of electronic parts. 12:43:58 PM 4
- 5. 5 MAJOR COMPONENTS OF A COMMON PLC PROCESSOR POWER SUPPLY I M N O P D U U T L E O M U O T D P U U L T E PROGRAMMING DEVICE From SENSORS Pushbuttons, contacts, limit switches, etc. To OUTPUT Solenoids, contactors, alarms etc. 12:43:58 PM 5
- 6. 6 MAJOR COMPONENTS OF A COMMON PLC POWER SUPPLY Provides the voltage needed to run the primary PLC components I/O MODULES Provides signal conversion and isolation between the internal logic- level signals inside the PLC and the field’s high level signal. PROCESSOR Provides intelligence to command and govern the activities of the entire PLC systems. PROGRAMMING DEVICE Used to enter the desired program that will determine the sequence of operation and control of process equipment or driven machine. 12:43:58 PM 6
- 7. PROGRAMMING LANGUAGES OF PLC Most common languages encountered in PLC programming are: 1) Ladder Logic 2) Functional Block Diagram 3) Sequential Function Chart 4) Boolean mnemonics 12:43:58 PM 7
- 8. Ladder Logic It is well suited to express Combinational logic. The main ladder logic symbols represent the elements : 12:43:58 PM 8
- 9. NOR Gate A B Y A B Logic(Y) OFF OFF ON ON OFF ON OFF ON ON ON ON OFF A B Logic(Y) OFF OFF ON ON OFF ON OFF ON ON OFF OFF OFF NAND Gate B Y A 12:43:58 PM 9
- 10. Ladder Logic Program for Start/Stop of Motor : X2X1 Y1 Y1 12:43:58 PM 10
- 11. Reliability. Flexibility in programming and reprogramming. Cost effective for controlling complex systems. Small physical size, shorter project time. High speed of operation. Ability to communicate with computer systems in the plant. 12:43:58 PM 11
- 12. Disadvantages of PLCs PLC devices are proprietary it means that part or software of one manufacturer can’t be used in combination with parts of another manufacturer. Limited design and cost option Fixed Circuit Operations. PLCs manufacturers offer only closed architectures. 12:43:58 PM 12
- 13. Wherever automation is desired the PLCs are best suited to meet the task. Few examples of industries where PLCs are used : 1) Robots manufacturing and control 2) Car park control 3) Train control station system 4) Food processing 12:43:58 PM 13
- 14. Conclusion Programmable logic controller or plc as it universally called is of industrial automation. Plc have been gaining popularity on the factory floor. For some time to core plc are an application area where much can be done . 12:43:58 PM 14
- 15. Thank You 12:43:58 PM 15