Implementation and Verification of Distributed Control Systems
Christian Gerber
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Christian Gerber, Implementation and Verification of Distributed Control Systems (2011), Logos Verlag, Berlin, ISBN: 9783832597726
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Beschreibung / Abstract
There exist certain key issues to modern industrial automation as modularity, reusability, portability, flexibility, extendibility and reconfigurability to create optimally coordinated automation solution for manufacturing plants. This will feature the operating companies to react fast and flexible to changed customer demands. An appropriate way to realize these issues is an object-oriented control implementation, which has been quite common since the late 90s.
This work is focused on the upcoming standard IEC 61499, which defines an object-oriented and event-driven software model, which can be realised by any hardware the engineer prefers. Furthermore, the control implementation is application-oriented and all parts are mapped to available control devices later on. Thus, it is possible to replace one device by another by easily remapping the application. But, does this possibility need certain care during the development of the control application and how could a control engineer be supported to prove the correctness of the plant behaviour in any case?
To answer this question the formal model discrete timed Net Condition/Event Systems is used in this work to model in a modular manner the control system and the plant. Both models are connected in closed loop to perform a reachability analysis. It is shown, how a control engineer can examine in a graphical manner the system behaviour for all possible cases by selecting interesting trajectories and drawing them as Gantt-Charts. Since the model of the plant incorporates all sensors and actuators, the state of the corresponding places can be included into the Gantt-Chart.
Even if the control engineer has no deep knowledge about the used formal model, this systematic and tool supported way ensures the possibility to analyse the system behaviour in any case, if he changes the control application or remaps it. This will reduce downtimes during production changes and new plant can be brought faster into service.
This work is focused on the upcoming standard IEC 61499, which defines an object-oriented and event-driven software model, which can be realised by any hardware the engineer prefers. Furthermore, the control implementation is application-oriented and all parts are mapped to available control devices later on. Thus, it is possible to replace one device by another by easily remapping the application. But, does this possibility need certain care during the development of the control application and how could a control engineer be supported to prove the correctness of the plant behaviour in any case?
To answer this question the formal model discrete timed Net Condition/Event Systems is used in this work to model in a modular manner the control system and the plant. Both models are connected in closed loop to perform a reachability analysis. It is shown, how a control engineer can examine in a graphical manner the system behaviour for all possible cases by selecting interesting trajectories and drawing them as Gantt-Charts. Since the model of the plant incorporates all sensors and actuators, the state of the corresponding places can be included into the Gantt-Chart.
Even if the control engineer has no deep knowledge about the used formal model, this systematic and tool supported way ensures the possibility to analyse the system behaviour in any case, if he changes the control application or remaps it. This will reduce downtimes during production changes and new plant can be brought faster into service.
Inhaltsverzeichnis
- BEGINN
- 1 Introduction and Motivation
- 1.1 Focused on IEC 61499
- 1.2 Proposed Solution Approach
- 1.3 Structure of the thesis
- 2 Formal Modelling Language
- 2.1 Syntax Definition
- 2.2 Semantic Definition
- 2.3 Markup Language
- 2.4 Implementation of a Workbench
- 2.5 Library of often used Plant Modules
- 2.6 Summary
- 3 Control Implementation Approaches
- 3.1 Short Introduction to IEC 61499
- 3.2 Central Controller Approach
- 3.3 Master-Task-Controller Approach
- 3.4 Parametrized Master-Task-Controller Approach
- 3.5 Workpiece Controller
- 3.6 Servo-Control System
- 3.7 Summary
- 4 Formal Modelling of the IEC 61499 elements
- 4.1 Execution Model
- 4.2 Data Processing Model
- 4.3 Scheduling Model
- 4.4 Summary
- 5 Closed-Loop Modelling
- 5.1 Transformation Process
- 5.2 Model of the Control Device
- 5.3 Plant Model
- 5.4 Summary
- 6 Verfication Results
- 6.1 Central Controller
- 6.2 Master-Task-Controller
- 6.3 Workpiece Controller
- 6.4 Summary
- 7 Conclusions
- 7.1 Summary of the thesis
- 7.2 Ongoing work
- 7.3 Long-term vision