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237-1060-E, 2 +2 PLC in Industrial Control

237-1060-E, 2 +2 PLC in Industrial Control . Ing. Marie Martinásková, Ph.D. Ing. Jakub JURA. Czech Technical University in Prague Mechanical Engineering Faculty Institute of Instrumentation and Control Engineering Technická 4, 166 07 Prague 6.

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237-1060-E, 2 +2 PLC in Industrial Control

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  1. 237-1060-E, 2+2PLC in Industrial Control Ing. Marie Martinásková, Ph.D. Ing. Jakub JURA

  2. Czech Technical University in PragueMechanical Engineering Faculty Institute of Instrumentation and Control EngineeringTechnická 4, 166 07 Prague 6

  3. The Head of the Institute of Instrumentation and Control EngineeringProf. Ing. Pavel ZÍTEK, Dr.Sc.Room 413, Dejvice

  4. Ing. Marie Martinásková, Ph.D.Lectures,exercises, laboratoryroom: 511 Dejvicephone to the room:224352528email:martinas@fsid.cvut.cz mobil:732605047

  5. Ing. Tomáš Vyhlídal, Ph.D.Exercises, laboratoryroom: 305i Dejvicephone to the room:22435….email:………..@fsid.cvut.cz

  6. Lectures:Thuersday 10.45 room 109 DejviceExercises, laboratory:Thuersday: 12.30 room 109 Dejvice

  7. Lecture 1 1.The PLC in automation technology 1.1 Introduction 1.2 Areas of application of a PLC 1.3 Basic design of a PLC 1.4 The new PLC standard IEC 1131

  8. 1.The PLC in automation technology

  9. 1.1 Introduction

  10. PLC Programmable Logic Controller The first PLC was developed by a group of engineers at General Motors in 1968, when the company were looking for an alternative to replace complex relay control systems.

  11. The new control system had to meet the following requirements: • Simple programming • Program changes without system intervention (no internal rewiring) • Smaller, cheaper and more reliable than corresponding relay control systems • Simple, low cost maintenance

  12. Subsequent development resulted in a system enabled: • the simple connection of binary signals • the requirements as to how these signals were to be connected was specified in the control program • with the new systems it became possible for the first time to plot signals on a screen and to store these in electronic memories

  13. More then three decades have passed: • the enormous progress was made in the development of micro electronics • great influence also at PLCs • For instance, even if program optimisation and thus a reduction of required memory capacity initially still represented an important key task for the programmer, nowadays this is hardly of any significance.

  14. Evolution….. • the range of functions has grown considerably • 15 years ago, process visualisation, analogue processing or even the use of a PLC as a controller, were considered as Utopian….. • nowadays, the support of these functions forms an integral part of many PLCs.

  15. 1.2 Areas of application of a PLC

  16. Every system or machine has a controller.Depending on the type of technology used, controllers can be divided into: • pneumatic • hydraulic • electrical • electronicFrequently, a combination of different technologies is used.

  17. Furthermore, differentiation is made between: • hard-wired programmable (e.g. wiring of electromechanical or electronic components) controllers • programmble logic controllers

  18. Hard-wired programmable controllers - 1 • This first type of controller is used primarily in cases, where any reprogramming by the user is out of the question and the large job size warrants the development of a special controller.

  19. Hard-wired programmable controllers - 2 Typical applications for such controllers can be found in : • automatic washing machines • cameras • video cameras • mobile phones • cars etc.

  20. Universal controllers -1 However, if the smallerjob size does not warrant the development of a special controller or if the user is to have the facility of making simple or independent program changes, or of parameter changes(e.g.setting timers and counters), then the use of a universal controller, where the program is written to an electronic memory, is the preferred option…the second one possibility.

  21. Universal controllers -2 The PLC represents such a universal controller! It can be used for different applications and, via the program installed in its memory, provides the user with a simple means of changing, extending and optimising control processes.

  22. Universal controllers -3 Application areas of PLCs: • production machines • production lines • production processes • environmentally systems (waste water cleaning,….) • building equipment systems (heating,cooling, lighting, safety systems…)

  23. The original task of a PLC • the interconnection of input signals according to a specified program and switching corresponding output signals • both input and output signals are supposed to be logical ones • Boolean algebra forms the mathematical basis for this operation, which recognises precisely two defined statuses of one variable: "O" and "1 "

  24. New tasks of a PLC However the tasks of a PLC have rapidly multiplied: • timer and counter functions • memorysetting and resetting • mathematical computing operations All this represent functions, which can be executed by practically any of today's PLCs.

  25. Further Development of PLCs-1 • The demands to be met by PLC's continued to grow in line with their rapidly spreading usage and the development in automation technology • Visualisation, i.e. the representation of machine statuses such as the control program being executed, via display or monitor.

  26. Further Development of PLCs -2 • Also supervising, i.e. the facility for human to intervene in control processes or, alternatively, to make such intervention by unauthorised persons impossible. • Very soon, it also became necessary to interconnect and harmonise individual systems controlled via PLC by means of automation technology – PLC networks. • Hence a master computer facilitates the means to issue higher-level commands for program processing to several PLC systems.

  27. Networking of several PLCs • The networking of several PLCs as well as that of a PLC and master computer is effected via special communication interfaces. • To this effect, many of the more recent PLCs are compatible with open, standardised bus systems, such as Profibus to DIN 19 245. • Thanks to the enormously increased performance capacity of advanced PLCs, these can even directly assume the function of a master computer.

  28. PLC - not only for logic control-1 • At the end of the seventies, binary inputs and outputs were finally expanded with the addition of analogue inputs and outputs, since many of today's technical applications require analogue processing (force measurement, speed setting, servo-pneumatic positioning systems etc. at machine tools).

  29. PLC - not only for logic control-2 • At the same time, the acquisition or output of analogue signals permits an actual/setpoint value comparison and as a result the realisation of automatic control engineering functions, a task, which widely exceeds the scope suggested by the name (programmable logic controller).

  30. Currently PLCs - 1 • The PLCs currently on offer in the market have been adaped to the customer requirements to such an extent that it has become possible to purchase an eminently suitable PLC for virtually any application • Miniature PLCs with a minimum number of inputs/outputs (6/4 IOs) and also large PLC systems with thousands of IOs are available today

  31. Currently PLCs - 2 • Many PLCs can be expanded by means of additionallogic input/output, analogue input/output, positioning and communicationmodules • Special PLCs are available for safety technology, shipping tasks, mining tasks etc.

  32. Currently PLCs - 3 • Yet further PLCs are able to process several programs „simultaneously“ – multitasking or truly simultaneously – multiprocessing (more processors in one PLC) • Finally, PLCs are coupled with other automation components (HMI, identification systems, smart actuators, etc.) thus creating considerably wider areas of application

  33. 1.3 Basic design of a PLC

  34. The term 'programmable logic controller' is defined as follows by lEC 1131, Part 1:"PLC is a digitally operating electronic system, designed for use in an industrial environment, which uses a programmable memory for the internal storage of user-oriented instructions for implementing specific functions such as logic, sequencing, timing, counting and arithmetic, to control, through digital or analog inputs and outputs, various types of machines or processes. Both the PC and its associated peripherals are designed so that they can be easily integrated into an industrial control system and easily useď in all their intended functions. "

  35. So we can say that programmable logic controller is therefore nothing more thana microcomputer, tailored specifically for certain control tasks

  36. System components of a PLCPLC Program

  37. System components of a PLCPLC Program HW

  38. System components of a PLCPLC Program SW HW

  39. System components of a PLCPLC Program SW PLC HW

  40. PLC and FieldPLC Program SW PLC HW FIELD

  41. PLC, Field and Controlled systemPLC Program SW PLC HW FIELD CONTROLLED PROCESS or CONTROLLED MACHINE

  42. Function of input and output module • The function of an input module is to convert incoming signals from sensors into signals which can be processed by the PLC and to pass these to the central control unit. • The reverse task is performed by an output module. This converts the PLC signal into signals suitable for the actuators

  43. Function of CPU • The actual processing of the signals is effected in the central control unit (CCU) in accordance with the program stored in the memory. • Another name for CCU : CPU = Central processing unit is often used

  44. The program of a PLC can be created in various ways: • via assembler- type commands in 'statement list' • in higher-level, problem-oriented languages such as structured text • in the form of a flow chart such as represented by a sequential function chart • in Europe, the use of function block diagrams based on function charts with graphic symbols for logic gates is widely used • in America, the 'Iadder diagram' is the preferred language by users

  45. External design of PLC Depending on how the central control unit (CCU) is connected to the input and output modules, ditferentiation can be made between: • compact PLCs (input module, central control unit and output module in one housing) • modular PLCs

  46. Modular PLCs • Modular PLCs may be configured individually. The modules required for the practical application - which can, for instance, include digital input/output modules, analogue modules, positioning and communication modules - are inserted in a rack, where individual modules are linked via a bus system. This type of design is also known as series technology.

  47. Modular PLCs - examples • Two examples of modular PLCs are shown on the following figures. • These represent • the familiar modular PLC FPC405 FESTO • the new S7 -300 series by Siemens.

  48. PLC plug-in cards (Festo FPC 405)

  49. Modular PLC – card format • The card format PLC is a special type of modular PLC, developed during the last years of previous century. • With this type, individual or a number of printed circuit board modules are in a standardised housing. • The Festo FPC 405 is representative of this type of design (Fig.).

  50. Modular PLC - Siemens S7-300

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