Alfred Theorin

An event-driven manufacturing information system architecture for Industry 4.0

Future manufacturing systems need to be more flexible, to embrace tougher and constantly changing market demands. They need to make better use of plant data, ideally utilising all data from the entire plant. Low-level data should be refined to real-time information for decision-making, to facilitate competitiveness through informed and timely decisions. The Line Information System Architecture (LISA), is presented in this paper. It is an event-driven architecture featuring loose coupling, a prototype-oriented information model and formalised transformation services. LISA is designed to enable flexible factory integration and data utilisation. The focus of LISA is on integration of devices and services on all levels, simplifying hardware changes and integration of new smart services as well as supporting continuous improvements on information visualisation and control. The architecture has been evaluated on both real industrial data and industrial demonstrators and it is also being installed at a large automotive company. This article is an extended and revised version of the paper presented at the 2015 IFAC Symposium on Information Control in Manufacturing (INCOM 2015). The paper has been restructured in regards to the order and title of the chapters, and additional information about the integration between devices and services aspects have been added. The introduction and the general structure of the paper now better highlight the contributions of the paper and the uniqueness of the framework.

Service-Oriented Process Control with Grafchart and the Devices Profile for Web Services

To fulfill increasing requirements within the manufacturing sector, highly flexible and adaptable automation systems are needed. It is desirable to have one integrated approach that stretches from the process planning phase, through the implementation phase and all the way to the phase for execution of the process control logics. One promising approach is to use the concepts of service-oriented architectures within automation, here referred to as SOA-AT. As service technology, DPWS has proved to be the most suitable for realizing service based communication on device level. The paper shows how Grafchart, a graphical language aimed for sequential control applications, can support the development of DPWS applications, and how Grafchart can be used for process modeling and execution in the planning and execution phase. This constitutes a unique framework for the development and execution of SOA applications in accordance with the requirements for automatic control tasks. The paper also presents an industry-related experimental setup in which the SOA-AT concepts are demonstrated through the use of Grafchart.

Towards a seamless integration between process modeling descriptions at business and production levels: work in progress

To fulfill increasing requirements in the manufacturing sector, companies are facing several challenges. Three major challenges have been identified regarding time-to-market, vertical feedback loops, and level of automation. Grafchart, a graphical language aimed for supervisory control applications, can be used from the process-planning phase, through the implementation phase and all the way to the phase for execution of the process control logics, on the lower levels of the automation triangle along the life cycle axis. This work in progress examines that the same process-based engineering approach can be used on the higher levels of the automation triangle along the enterprise axis interconnecting both axes. By splitting the execution engine and the visualization engine of Grafchart various different visualization tools could potentially be used, however connected by the shared Grafchart semantics. Traditional Business languages (e.g. BPMN) could therefore continue to be used for the process-planning phase whereas traditional production languages (e.g. Grafchart or other sequential function charts-like languages) could be used for the execution. Since they are connected through the semantics, advantages regarding the three identified challenges could be achieved: time-to-market could be reduced, the time delays in the vertical feedback loops could be reduced by Key Performance Indicator visualization and eventing, and the level of automation could be increased.

A reference architecture for service-oriented control procedures and its implementation with SysML and Grafchart

Innovative engineering methods are needed to enhance the adaptability and agility of industrial control procedures and concurrently manage their rising complexity. Service-oriented Architecture (SOA) constitutes a promising paradigm to meet these challenges. To apply the rather abstract SOA principles to industrial automation, a model-driven engineering method is presented in this paper. Therefore, a reference architecture is introduced providing a framework to structure and define services for control tasks in a convenient way. The application of the engineering method is supported by an implementation concept. It uses SysML during the design phase and the process modeling and control language Grafchart for the execution of service-oriented control procedures.

An Interactive PID Learning Module for Educational Purposes

The PID controller is the most common controller and it is taught in most introductory automatic control courses. To develop an intuitive understanding of the basic concepts of the PID controller and PID parameter tuning, interactive and freely available tools are important. A PID module for educational purposes has been implemented in JGrafchart, a freely available development environment for the graphical programming language Grafchart. JGrafchart includes interactive graphical elements such as live plots and it is possibile to create animated graphics, for example of a simulated process. JGrafcharts variables, for example controller parameters and modes, can be changed interactively while executing. The PID module will be included in future releases of JGrafchart with sample applications which can be used for example to demonstrate a PID controller live in lectures or to let students interactively change controller parameters and modes to develop an intuitive understanding of the PID controller and PID parameter tuning. The sample applications are designed for users without any knowledge about JGrafchart and can be used to control both simulated and physical processes.

Service orchestration with OPC UA in a graphical control language

Production plants need to be set up and reconfigured faster to fulfill increasing market demands. Highly flexible automation systems are needed and a promising approach is Service Oriented Architecture (SOA) which has recently received much attention in both academia and industry. OPC Unified Architecture (OPC UA), the next generation of the de facto standard for interoperability in the automation domain, has SOA capabilities. In this paper it is presented how SOA service orchestration of OPC UA services can be done conveniently with a graphical control language. Generic support to use OPC UA servers has been integrated into the language and as an example it has been used to control a physical process which has been modeled, encapsulated, and exposed as an OPC UA server by wrapping it with an ethernet capable microcontroller.

Implementation of an asymmetric relay autotuner in a sequential control language

Control applications contain both logic, sequencing, and control algorithms. A holistic view of this is seldom presented in teaching and papers. One reason is the separation of communities - automation groups typically come from the Programmable Logic Controller (PLC) world while control engineers primarily come from the Distributed Control System (DCS) world. Both logic, sequencing, and control algorithms are, however, well integrated in todays control systems since DCS systems now contain logic and sequencing and PLCs now contain control algorithms. This paper shows that both logic, sequencing, and control algorithms can be integrated seamlessly in a sequential control language. The particular application considered is a PID controller with a relay autotuner. The presented autotuner implementation yields good controller parameters and is freely available.

Towards a seamless integration between process modeling descriptions at Business and Production levels - work in progress

To fulfill increasing requirements in the manufacturing sector, companies are faced with several challenges. Three major challenges have been identified regarding time-to-market, vertical feedback loops and level of automation. Grafchart, a graphical language aimed for supervisory control applications, can be used from the process-planning phase, through the implementation phase and all the way to the phase for execution of the process control logics, on the lower levels of the Automation triangle. Work in progress is examining if the same concepts could be used on the higher levels of the Automation triangle as well. By splitting the execution engine and the visualization engine of Grafchart various different visualization tools could potentially be used, however connected by the shared Grafchart semantics. Traditional Business languages, e.g. BPMN, could therefore continue to be used for the process-planning phase whereas traditional production languages, e.g. Grafchart or other SFC-like languages, could be used for the execution. Since they are connected through the semantics, advantages regarding the three identified challenges could be achieved; time-to-market could be reduced, the time delays in the vertical feedback loops could be reduced by allowing KPI visualization, and the level of automation could be increased.