The research project Architecture and Interfaces of a Web-oriented Automation System (WOAS) was initiated in 2011 launched by the Competence Center Automation Duesseldorf (CCAD) with participation of 10 German automation companies. The aim of the research project is to look into a new architecture for automation systems based on web technologies. Based on the technological approach familiar from the IT sector involving a web-oriented architecture (WOA), this architecture is referred to as a web-oriented automation system (in short: WOAS). A WOAS comprises a WOAS kernel as well as a configurable number of web-oriented automation services (WOAD), that realize the required automation functions.
A consistent architecture model for web-oriented automation solutions (reference model) is to be created with the WOAS/WOAD method, which forms the basis for establishing concrete automation systems distributed in an IP network. Even if reference is frequently made to process visualization/HMI systems as a typical example to illustrate a practical application, a WOAS can basically realize every possible automation function (AF) above the field level. This is only dependent on the relevant concrete requirements for the AF. Based on the model notation to be developed and the engineering tools to be established on this, the WOAS model handles the entire life cycle of an automation system, from tool-assisted generation and operation through to updating and maintenance.
Fig. 1 shows the principle structure of a WOAS. The whole automation system is created by the user in the web browser through an internal build specification (SK = system kernel) that is stored in a database. The required AF are utilized as automation services (AS in Fig. 1) via a WOAS cloud. The device binding in a WOAS is made by Virtual Devices (VD), which describe (map) the real automation devices as a CPS component in the Web-world. A VD in WOAS maps the relevant technical process via process data. This can be an individual sensor or also a complete field system with control, sensors and actuators.
All elements of a WOAS including the engineering system (WOAS creator) can be accessed via the web.
Based on the new paradigm of CPS-based Automation (Fig. 2) the prototype of a WOAS portal for creation and operation of automation systems is implemented as a CPS Integration Platform. This CPS Integration Platform can connect and configure different real automation devices as Cyber Physical System components (CPS components) with any services (automation services) from a cloud.
Thereby a CPS component is defined as a real physical object which is connected with information-processing objects and processes over open, partial global and at any time connected information networks.
The WOAS portal is a role-based user system (Fig.3). The system contains an engineering environment (WOAS creator) to configure a user-specific WOAS, consisting of n websites (views) usually containing a WOAS kernel respectively. In principle each functionality which is programmable by Web technology can be used as a service in a WOAS system e.g. sending of SMS and emails, use of Google Apps, MashUps and Webservice applications. Important for a WOAS system is only to have a correct and defined WOAS service interface on the top of the implemented service.
First time with the prototype of the WOAS portal is a CPS integration platform as a configuration and runtime environment online, by which global distributed automation devices (CPS components) with arbitrary distributed services (CPS services) can be built in the browser as an application-specific functional system and can be used for a test run. Another unique feature compared to all other cloud-based integration systems for production automation, the WOAS portal can be extended by any third party with services and other devices through consistent and open interfaces.
The WOAS architecture gives small and medium-sized companies in particular an opportunity to provide highly-flexible and "lean" automation solutions for the sector typical of the customer-specific device/machine and plant engineering quickly and cost effectively. High licence and maintenance costs for the normally large process control and SCADA system are no longer required - only the services are used (and paid for) that are actually needed for the relevant automation task.
The research results are intended to enable, amongst other benefits, the development of new, universal web-oriented automation systems that can be adapted to application-specific needs with the utmost flexibility and very little expense (Lean Web Automation). Furthermore, available automation systems can distribute functionalities with web orientation in an IP net-work based on the model and interface notations to be developed in the project and hence extend their range of applications. The additional use of web-oriented automation services with Web 2.0-technologies allows the available systems to be upgraded significantly, thereby extending their useful life cycle.
Prof. Dr.-Ing. Reinhard Langmannn, info(at)ccad.eu