OPC Unified Architecture

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1 Wolfgang Mahnke Stefan-Helmut Leitner Matthias Damm OPC Unified Architecture Springer

Table of Contents Foreword by Tom Burke Foreword by Jim Luth Preface About the Authors Acknowledgements v vii ix xiii xv 1 Introduction 1 1.1 OPC Foundation 1 1.2 Classic OPC 3 1.2.1 OPC Data Access 4 1.

2 Table of Contents Foreword by Tom Burke Foreword by Jim Luth Preface About the Authors Acknowledgements v vii ix xiii xv 1 Introduction OPC Foundation Classic OPC OPC Data Access OPC Alarm and Events OPC Historical Data Access Other OPC Interface Standards OPC XML-DA Motivation for OPC UA OPC UA Overview OPC UA Specifications OPC UA Software Layers Evolution Not Revolution Summary Key Messages Where to Find More Information? What's Next? 17 2 Information Modeling: Concepts Why Information Modeling? Nodes and References ReferenceTypes Objects, Variables and Methods Types for Objects and Variables Simple ObjectTypes Simple VariableTypes Complex ObjectTypes InstanceDeclarations Complex VariableTypes ModellingRules Subtyping of ComplexTypes Data Variables and Properties 58 xvii

xviii Table of Contents 2.7 ModelParent for Objects, Variables and Methods 60 2.8 DataTypes 61 2.8.1 DataType NodeClass 62 2.8.2 Built-in and Simple DataTypes 63 2.8.3 Enumeration DataTypes 63 2.8.4 Structured DataTypes 64 2.

3 xviii Table of Contents 2.7 ModelParent for Objects, Variables and Methods DataTypes DataType NodeClass Built-in and Simple DataTypes Enumeration DataTypes Structured DataTypes Specific Built-in DataTypes Summary on DataTypes Views Events Historical Access Historical Data Historical Events Historical Address Space Address Space Model and Information Models Summary Key Messages Where to Find More Information? What's Next? 84 3 Information Modeling: Example and Best Practice Overview Example Application Scenario Simple Scenario - Similar to Classic OPC Advanced Scenario - Providing Full Power of OPC UA Best Practices Structuring with Objects, ReferenceTypes and Views TypeDefinitions (Obj ecttypes and VariableTypes) Providing Complex Data Structures Providing User-Defined DataTypes Properties 102 3:3.6 Methods ModellingRules Proxy Objects (Properties on References) Summary Key Messages Where to Find More Information? What's Next? Standard Information Models Overview Handling Information Models What is Specified by an Information Model? How is an Information Model Specified? Ill

Table of Contents xix 4.2.3 How are Multiple Information Models Supported? Ill 4.3 Base OPC UA Information Model 112 4.4 Capabilities and Diagnostics 115 4.5 Data Access 115 4.

4 Table of Contents xix How are Multiple Information Models Supported? Ill 4.3 Base OPC UA Information Model Capabilities and Diagnostics Data Access Historical Access and Aggregates State Machine Programs Alarms and Conditions Domain-Specific Information Models Overview Devices Information Model Summary Key Messages Where to Find More Information? What's Next? Services Overview General Service Concepts Timeout Handling Request and Response Headers Error Handling Extensible Parameters Communication Context Convention for Describing Services in this Chapter Finding Servers Service FindServers Service GetEndpoints Service RegisterServer Connection Management Between Clients and Servers Secure Channel Establishment Creating an Application Session Closing an Application Session Cancel Outstanding Service Requests Find Information in the Address Space Services Used for Discovering the Address Space Use Cases for Finding Information in the Address Space Read and Write Data and Metadata Reading Data Writing Data Subscribe for Data Changes and Events Delivery of Changed Data and Events Create and Manage Subscriptions Create and Manage Monitored Items Monitor Data Changes 171

xx Table of Contents 5.7.5 Monitor Events 173 5.7.6 Monitor Aggregated Data 175 5.8 Calling Methods Defined by the Server 176 5.9 Access History of Data and Events 177 5.9.1 HistoryRead Service 177 5.

5 xx Table of Contents Monitor Events Monitor Aggregated Data Calling Methods Defined by the Server Access History of Data and Events HistoryRead Service HistoryUpdate Service Find Information in Complex Address Space Modify the Address Space Adding Nodes Creating References Between Nodes Removing Nodes Delete References Between Nodes Summary Key Messages Where to Find More Information? What's Next? Technology Mapping Overview Data Encodings OPC UA Binary XML Security Protocols WS-SecureConversation UA-SecureConversation Transport Protocols UA TCP SOAP/HTTP Available Mapping Implementations Summary Key Messages Where to Find More Information? What's Next? Security Why is Security so Important? Organizational Perspective of Security Technical Perspective of Security Determining The Appropriate Level of Security Security Assessments The OPC UA Security Assessment The OPC UA Security Model Security Architecture Securing the Communication Channel 212

Table of Contents xxi 7.5.3 Authentication and Authorization 218 7.5.4 Security Policies and Profiles 222 7.6 Certificates 222 7.6.1 What is a Certificate? 222 7.6.2 OPC UA Certificates 224 7.

6 Table of Contents xxi Authentication and Authorization Security Policies and Profiles Certificates What is a Certificate? OPC UA Certificates Public Key Infrastructure for OPC UA What is a PKI? Trust Models Certificate Lifecycle Management Available PKI Frameworks PKI for Industrial Applications Summary Key Messages Where to Find More Information? What's Next? Application Architecture Introduction Architectural Overview Stack Interface Encoding Layer Security Layer Transport Layer Platform Layer Software Development Toolkit UA-Specific Functionality Common Functionality Interfaces Application Client Server Deliverables Provided by the OPC Foundation Stacks SDKs Applications Summary Key Messages Where to Find More Information? What's Next? System Architecture System Environment Basic Architecture Patterns Client-Server Chained Server 266

xxii Table of Contents 9.2.3 Server-to-Server Communication 267 9.2.4 Aggregating Server 268 9.3 Redundancy 269 9.3.1 Client Redundancy 269 9.3.2 Server Redundancy 270 9.4 Discovery 273 9.4.1 Why discovery?

7 xxii Table of Contents Server-to-Server Communication Aggregating Server Redundancy Client Redundancy Server Redundancy Discovery Why discovery? Discovery Entities Discovery Process Auditing Overview Audit Logs Audit Events Service Auditing Use Cases Summary Key Messages Where to Find More Information? What's Next? Mapping of COM OPC to OPC UA Overview OPC Data Access 2.05A and Address Space Access Information OPC XML-DA OPC Alarm and Events Address Space Access Information OPC Historical Data Access Address Space Access Information Summary Key Messages Where to Find More Information? What's Next? Migration Overview Wrappers - Access COM Server from UA Client Proxies - Access UA Server from COM Client Native Development Summary Key Messages Where to Find More Information? What's Next? 297

Table of Contents xxiii 12 Profiles 299 12.1 Motivation 299 12.2 Profiles, Conformance Units and Test Cases 299 12.3 Profiles for Server Applications 300 12.4 Profiles for Client Applications 301 12.

8 Table of Contents xxiii 12 Profiles Motivation Profiles, Conformance Units and Test Cases Profiles for Server Applications Profiles for Client Applications Transport Profiles Security Profiles Certification Process Summary Key Messages Where to Find More Information? What's Next? Performance Overview Performance Numbers Summary Key Messages Where to Find More Information? What's Next? Conclusion and Outlook OPC UA in a Nutshell Is OPC UA Complicated? Are OPC UA Services Difficult to Handle? Is Information Modeling a Pain? Transport Protocols and Encodings: Why So Many? Implementation Issues Migration of Existing Code Management Summary Outlook Literature 323 Appendix A: Graphical Notation 327 Motivation and Relation to UML 327 Notation 328 Example 330 Appendix B: NodeClasses and Attributes 333 Appendix C: Base Information Model Reference 335 Index 337

F O U N D A T I O N. OPC Unified Architecture. Specification. Part 1: Concepts. Version 1.00

F O U N D A T I O N. OPC Unified Architecture. Specification. Part 1: Concepts. Version 1.00 F O U N D A T I O N Unified Architecture Specification Part 1: Concepts Version 1.00 July 28, 2006 Unified Architecture, Part 1 iii Release 1.00 CONTENTS Page FOREWORD... vi AGREEMENT OF USE... vi 1 Scope...