Object-Oriented Programming with SIMOTION

Die Tendenz im Maschinenbau hin zu immer flexibleren Lösungen führt auch zu Veränderungen bei den Steuerungen. Mit der Zunahme mechatronischer Systeme und modularer Funktionseinheiten ergeben sich hohe Anforderungen an die Software und deren Programmierung. In der Automatisierungstechnik wird daher in den nächsten Jahren der gleiche Wandel stattfinden, der in der PC-Welt bereits erfolgt ist, hin zu besserem und klarerem Softwaredesign, zu einfacher Änderbarkeit und Modularität. Dafür brauchen wir Objektorientierte Programmierung.
Das Buch richtet sich an alle, die sich mit dieser zukunftsweisenden Entwicklung in der Automatisierungstechnik vertraut machen möchten. Egal ob man angehender Ingenieur, Techniker oder erfahrener Automatisierungstechniker ist: Es hilft, die Objektorientierte Programmierung zu verstehen und anzuwenden.
SIMOTION stellt ab Softwarestand 4.5 die Möglichkeit der Nutzung von OOP entsprechend IEC 61131-3 ED3, der Norm für speicherprogrammierbare Steuerungen, zur Verfügung. Das Buch unterstützt den Umgang mit dieser Denk- und Programmierweise und bietet Programmierbeispiele zu verschiedenen objektorientierten Techniken und den dabei wirkenden Mechanismen. Die Beispiele sind aufeinander aufbauend gestaltet, so dass am Ende ein komplettes, verwendbares Maschinenmodul entsteht.

Autorentext

Michael Braun ist Produktmanager für Motion Control Engineering bei Siemens in Erlangen. Zu seinen Aufgaben gehört es, Kundenanforderungen in die Entwicklung einzuspeisen, deren Umsetzung zu verfolgen und aktuelle Software in den Markt einzuführen.
Dr. Wolfgang Horn ist Softwaremanager und -entwickler bei der Gesellschaft für Industrielle Steuerungstechnik in Chemnitz. Er ist intensiv vertraut mit der Architektur und Programmierung von SIMOTION.
Kurzvita Autor:
Michael Braun ist Produktmanager für Motion Control Engineering bei Siemens in Erlangen.
Dr. Wolfgang Horn ist Softwaremanager und -entwickler bei der Gesellschaft für Industrielle Steuerungstechnik in Chemnitz.

Zusammenfassung
In mechanical engineering the trend towards increasingly flexible solutions is leading to changes in control systems. The growth of mechatronic systems and modular functional units is placing high demands on software and its design. In the coming years, automation technology will experience the same transition that has already taken place in the PC world: a transition to more advanced and reproducible software design, simpler modification, and increasing modularity. This can only be achieved through object-oriented programming.

This book is aimed at those who want to familiarize themselves with this development in automation technology. Whether mechanical engineers, technicians, or experienced automation engineers, it can help readers to understand and use object-oriented programming.

From version 4.5, SIMOTION provides the option to use OOP in accordance with IEC 61131-3 ED3, the standard for programmable logic controllers. The book supports this way of thinking and programming and offers examples of various object-oriented techniques and their mechanisms. The examples are designed as a step-by-step process that produces a finished, ready-to-use machine module.

Contents: Developments in the field of control engineering - General principles of object-oriented programming - Function blocks, methods, classes, interfaces - Modular software concepts - Object-oriented design, reusable and easy-to-maintain software, organizational and legal aspects, software tests - I/O references, namespaces, general references - Classes in SIMOTION, instantiation of classes and function blocks, compatible and efficient software - Introduction to SIMOTION and SIMOTION SCOUT.

Inhalt

Information for readers 13

1 Developments in the Field of Control Engineering 1 18

1.1 The early days of programmable logic controllers (PLCs) 1.1 19

1.2 The PLC learns to communicate 1.2 22

1.3 Development of fieldbus systems 1.3 24

1.4 Integration of display systems in PLCs 1.4 25

1.5 Integration of motion control in PLCs 1.5 27

1.6 Drives become fully-fledged bus system nodes 1.6 30

1.7 PLC and PAC what is the difference? 1.7 31

1.8 General conclusions about past developments 1.8 31

2 Basic Principles of Object-Oriented Programming 2 33

2.1 The basis of object-oriented programming 2.1 33

2.1.1 History 33

2.1.2 What's different? 34

2.1.3 What does object orientation mean? 35

2.1.4 Objects and their interactions 36

2.2 General principles of OOP 2.2 37

2.2.1 Objects 37

2.2.2 Classes 39

2.2.3 Inheritance 39

2.2.4 Overriding 41

2.2.5 Interfaces for object interaction 42

2.2.6 Summary 44

2.2.7 Advantages of using OOP 45

2.2.8 Disadvantages of OOP 45

2.3 Tips about defining classes 2.3 46

3 Object-Oriented Programming 3 49

3.1 Implementation of OOP with SIMOTION 3.1 49

3.2 Function blocks with methods 3.2 50

3.2.1 Modularization without OOP extensions 51

3.2.2 Program and data are separate 53

3.2.3 Advances in the life cycle of software 55

3.2.4 Disadvantages of programming without OOP extensions 56

3.2.5 Extensions to FBs and their access specification 57

3.2.6 Use of methods to improve program structuring 59

3.2.6.1 Example of FB with methods 60

3.2.6.2 Example of a function block call 61

3.2.7 Function block with methods for placing commands 62

3.2.7.1 Example of the FB with command methods 63

3.2.7.2 Example of an FB call with command methods 65

3.3 Classes (CLASS) 3.3 66

3.3.1 Keywords supported for a class 67

3.3.1.1 Example of a CLASS declaration 69

3.3.2 Methods (METHOD) 69

3.3.3 Methods and their access specification 70

3.3.4 Declaration of instances of a class 71

3.3.5 Rules for identifiers in a class 72

3.3.6 Use of class methods 72

3.3.6.1 Example of a CLASS COUNTER 73

3.3.6.2 Use of the method of CLASS COUNTER 74

3.3.6.3 Extension of the CLASS COUNTER and use of THIS 75

3.3.6.4 Use of the methods UP and DOWN 76

3.3.7 Classes and inheritance 76

3.3.7.1 Example of derivation of a class 78

3.3.7.2 Example of how to use base and derived classes 79

3.3.7.3 Other aspects of the method call 80

3.3.7.4 Example of base and derived classes in a function 81

3.3.8 Abstract classes 82

3.4 Examples of valve applications with OOP 3.4 84

3.4.1 Example with 4/3-way valve 84

3.4.1.1 Example of a class for 4/3-way valves 85

3.4.1.2 Example of a valve call 87

3.4.1.3 Example with 4/3-way valve with fast/slow speed 88

3.4.1.4 Example of a derived class ValveControl43FS 89

3.4.1.5 Example of calls of base class and extended class 90

3.4.1.6 Example of call of extended class with basic function 91

3.5 Interfaces 3.5 92

3.5.1 Supported features 93

3.5.2 Principles of interfaces 94

3.5.2.1 Example of an interface declaration 95

3.5.3 Representation of interfaces in the PNV of SCOUT 97

3.5.4 Benefits of interfaces 99

3.5.5 Interfaces as a reference to classes 100

3.5.6 Valve classes with interfaces 103

3.5.7 Declaration of the valve interface 105

3.5.7.1 Example of ValveControl43 with limit switch monitoring 105

3.5.7.2 Example of ValveControl43 with error reporting 108

3.5.7.3 Example of ValveControl43 with test error reporting 112 3.5.7.4 Exam...