Remote Labs - Web Based System to Support Education Marián Bakoš, Iveta Zolotová, Ján Sarnovský Department of Cybernetics and Artificial Intelligence, FEI TU of Košice, Letná 9 041 20 Košice, Slovak Republic
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Abstract This article deals with an industrial portal as a subsystem of complex ICS - Information and Control Systems and its application as an education support tool. The emphasis is on the software and communication parts with the aim to integrate and distribute their functions in the ICS and application of Web based training oriented methods. It demonstrates the use of some of the applications within the framework of a model workshop for a complex ICS and selected control systems – cableway, intelligent house, temperature system, etc. Physical software architecture is built on the basis of DDE - Dynamic Data Exchange, OPC – OLE for Process Control and TCP/IP communication protocols. User interface e.g. with XML technology is available to clients of internet network, and this enables remote supervisory control with process visualization. The issue of long distance learning is a well known problem highly depending on the study material. Lots of various difficulties have arisen during the creation of this long distance study system. Issues are both on the pedagogical and technical levels. During the implementation of this industrial portal our traditional and mixed educational experiences, as well as our knowledge have been used and applied so that our students greatly benefit from and get acquainted with the models just as much as possible. Using standard web browser that is a usual component of operating system (or is available for free) looks like an ideal application to meet conditions resulted from long distance learning.
1. Introduction New theoretical knowledge, software, hardware and communication technology bring still the challenge of improving existing and designing new logical models and implementations of ICS – Information and Control Systems for variously enterprises. Their form depends on the level of abstraction, goals for application, scientific community or commercial use. One of variants of logical model is at “Fig. 1. Logical model of Information and Control Systems”. This hierarchical model includes e.g. SCADA/HMI- Supervisory Control, Data Acquisition, Human Machine Interface, MES - Manufacturing Execution System and MRP/ERP - Manufacturing Resource Planning/Enterprise Resource Planning
systems [2]. It emphasizes as well, that user's HMI can be not only at the level of supervisory control, but they can appear at higher levels of ICS. HMI can be available both locally and remotely, too. There are virtual or real controlled systems-models in education environment, in laboratories. The physical model of ICS implements a logical model into the concrete implementation environment, at the present time, usually as a certain computer system, which includes hardware, software and communication subsystems. Real laboratories are physically distributed in several rooms, departments, faculties, universities over the whole world [4]. The information industrial portal is a technology‘s answer to request for helping industry collaboration between the different people and companies that need to share the same information [3]. Systems for long distance learning provide support for students, i.e. materials and aids in the form of texts, electronic publications, software packages - they are didactically treated to help students to understand materials and be able to apply new knowledge. Our industrial portal gives opportunities to use it in teaching and learning by the help of Web based training oriented methods. We try to make it a part of our educational programme and give opportunity to know our models to other people that are interested in new information related to automatisation.
2. Web Based Training (WBT) E-learning technology/method WBT is characterised by following items: • • • • • •
online computer education education supported by web technologies teaching synchronous and asynchronous online courses studying materials are mostly available via web browser studying materials can be situated anywhere in the world (on the web) opportunities to work in the virtual classroom
3. Remote Supervisory Control The concept of a web-based laboratory is not new. Remote laboratories are essential to e-learning
platforms in scientific and technical disciplines. The internet totally changed the way of competitive fight by the customer’s access to applications anywhere in the world. Only a basic web browser is needed to gain access, the user can log on and post the parameters from a remote client to controlled systems, monitor current and historical situation in a remote-labs factory. Internet portal creates an entry gate to the world of information related to certain problem. Technology of thin-client („thin-client/server computing“) is a model where applications are accessible, administrated and operated fully on the server’s side. This technology provides advantages of better administration, access, performance and safety,
which help to reduce requirements imposed on property owners [1]. Types of remote laboratories are divided according to real or virtual model. First one is based on getting information from real models, visualisation, providing information in the form of numbers and graphs. Second one is based on the same features but models are only virtual and realized on the base of calculations, simulations (by the help of own algorithms in programmes or laboratory applications type Mathworks Matlab server / Simulink, National Instruments Labview) ... which help us to make calculations easier and make calculated results more accessible.
Fig. 1. – Logical model of Information and Control Systems We have several virtual-simulated and real-physical controlled systems with their ICS distributed in several laboratories. They serve as an educationalscientific workshop. A logic model is basically identical with the model shown in “Fig. 1. - Logical model of Information and Control Systems”. There are several real lab controlled systems, e.g. Heat system, Portal crane, Cableway, Intelligent house, Tube model, Traverse, Helicopter, Ball&Plate. The part of their ICSs is viewed at “Fig. 2. - Part of ICS model” and emphasizes possibility not only local control but remote one, too. Remote control may be served by industrial information server, in this case by SuiteVoyager from Wonderware corporation. This software organizes, secures and personalizes plant information, and gives users tools to view that information in a useful format for quick analysis. The
main advantage of this portal is image transfer speed, which is reached by online exporting of bitmap images into XML format on the side of the applications server. The portal is logically divided into parts that provide the students with model description, explanation of supervisory model control and makes model serving and long distance control available for all model functions that may be done in real time or in demo mode. The portal is available both in Slovak and English. A wide range of functions and accesses can be set on the portal. These settings and accesses are divided into the following groups with different accesses and authorisations (SVadmin, SVeng, SVuser). Feedback is given to the students by a ‘live’ camera view, data from the portal’s history saved in a
database and by model visualization. Explanations to individual models are enriched, enhanced by video previews of supervisory model control via the portal and at the same time the actual model behaviour is shown as well. Transparent and conspicuous model descriptions and their incorporation and division to different ICS levels are also shown. As for exercises, commands oriented at teaching the user to learn supervisory model control and access actual as well as history model data are available. The portal contains information on the laboratories as well, where the
models are situated. Panoramatic views allowing the visualization of model settings/placings and manipulation are also present at the portal. The remote lab is named CyberVirtLab in our DCAI and it is available from the address http://cybernetics.fei.tuke.sk/CyberVirtLab. This remote access is still under development. In spite of this, it suits remote distance learning courses, for their sharing facility of expensive instruments and equipment, for web based trainings in a real industrial portal environment.
Fig. 2. – Part of ICS model
3.1 Consistent views From the education point of view this web based training system provides learners via web HMI: • Theoretical part of WBT - Tutorial introduction, model description, user manual of supervisory control, exercises, • Practical part of WBT - monitoring and supervisory control and visualization, alarms, trends. There are designed consistent views for each controlled model in following structure: • Tutorial, Introduction – short description, photo or web cam, panorama,
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Model description – logical and physical models of whole controlled systems and their ICS systems, Supervisory control – user manual for HMI with demonstration video, Exercise, Visualization – multiviews – control panels for supervisory control, indicators, alarm status and acknowledgment, live video via web cam, Alarms – multiviews - current, historical alarms, History - adjustable history trend, portal history trend (30 min), portal history trend (8 hrs).
3.2 Short description of some models The Cableway model is processed as the model of an industrial device for the transportation of molten, liquid metal at metal melting in a blast furnace. Controlling is implemented as a network control system. Position sensors, as well as tensometers as connected to SLC via DeviceNet. The actual unit (direct engine) is also connected via DeviceNet network. The corf’s position is determined by the tensometers, while to implement changes the direct engine (actual unit) is used. Obstacles to the movement of weigh are the rail end switches. Controlling is implemented by the use of SLC. The SLC is connected to the server via the DH 485 network, where is provided the services of RSLinx GateWay communication program. In the Intelligent House model we try to regulate the temperature in the upper part of object and regulate the lighting in lower part of model. During the model implementation LonWorks modules from the sPoint series from SAMO Automation ltd. were used. The upper side of the building is a simulated room, where temperature is regulated. The source of heat is a bulb (heater) situated inside the object. A miniature ventilator is situated in the building, it serves as a deregulator, or a malfunction source. The lower part of the building consists of a simulated room where light controlling is situated. Light controlling is done either by setting the position of horizontal Venetian blind (available only locally) via a stepper, i.e. daylight or bulb light is used for illumination. Communication and regulation of model run by the help of LonWorks net that is created by sPoint modules. The Heat system is the model of primary side of the exchange unit used for water heating for central heating, or heating of hot utility water. It represents a closed circle of hot water. The water gains a certain level of heat from the spiral and this heat is then transferred to the water on the secondary side of the exchanger. Different technological nets were used in a model, e.g. M-BUS, HART, RIO and technological site DH485, that is used for connection between automaton and computer.
•
Practical part of WBT o visualisation - remote monitoring or supervisory control functions “Fig. 4. Visualisation” - indication and change of regime (automatic and manual), input of required values, display of real time values and parameters: actual location, orientation of motion, number of throughput, tolerance and calibration, live video to the cableway with control of lighting on/off, o current and historical alarms “Fig. 5. – Alarms” visualization and their acknowledgment, o trends (Figure 6) - acquisition of current and historical data and its graphical visualization.
Fig. 3. – Tutorial – User manual of Supervisory Control
4. Description of HMI Intelligent House model From the education point of view web based training system for real Intelligent House model and its real information and control system provides learners via web HMI: •
Theoretical part introduction, model supervisory control manual of
of WBT - tutorial description, user manual of “Fig. 3. - Tutorial – User Supervisory Control”.
Fig. 4. – Visualisation
complex hierarchical information and control systems, with emphasis SCADA/HMI systems. Industrial information portal appears as suitable tool for Web Based Training systems in educational and practical view.
6. Acknowledgement This paper is supported by the Slovak Grant Agency KEGA funded project 3/120603 and partly by Grant Vega 1/2185/05.
7. References Fig. 5. – Alarms
[1] M. Bakoš, Master thesis “Industrial Portal – Remote Laboratories” in Slovak, Košice 2005. [2] L. Landryová, “SCADA Applications based on .NET Architecture”. In: 5th Internation Carpathian Control Conference, Zakopane, Poland, AGH-UST Krakow, 25.– 28.5.2004, pp. 313-318, ISBN 83-89772-00-0. [3] I. Zolotová, J. Liguš, J. Jadlovský, J. Horváth, M. Duľa, S. Laciňák, “Remote Labs – Industrial Portal”, In: 5th International Conference Virtual University, 16.– 17.12.2004, Bratislava, Slovak Republic, ISBN 80-2272171-9. [4] I. Zolotová, B. Mihaľo, E. Ocelíková and L. Landryová, “Contribution to Models of Supervisory Control, Data Acquisition and Human Machine Interface”, Acta Electrotechnica et Informatica, No. 2, Vol. 2, 2002, pp. 6267, FEI TU Košice, Slovak Republic, ISSN 1335-8243.
Fig. 6. – Trends
5. Conclusion On the ground of useful thin-client, using internet technologies in remote learning appears appropriate thanks to accessing process data and visualisation of process, that has ability to contribute to knowledge and expansion of people’s qualifications. Our goal is to realize the internet industrial portal that could be used for teaching and presentation - Web Based Training orientated. This web based training is created in a real industrial portal environment. The advantage is that students work directly in the environment - to know the environment is a part of our pedagogical goal. The problem of multiplex access to real systems is here. Solution of this problem is based on proper administration, e.g. by scheduling remote lab sessions for trainers and learners, taking account of timetables of every participant. Only registered learners should interact, control remote systems. Trainers should be able to deal and take control on the system over learners. The main goal of Web Based Training systems is support to education in designing and using
[5] P. Vestenický, I.Krbiľová: “Perspectives of Information Networks Development”, In: Sborník přednášek celostátní konference s mezinárodní účastí TELEKOMUNIKACE ‘98. VUT, Brno 1998. [6] J. Liguš, J. Horanská: “The Principle of Direct Communication in Distributed Control Systems Design”. In: 12th EAEEIE Conference, Nancy, France, p. 6. , 2001. [7] P. Božek, F. Miksa: “Design of Manufacturing Systems”. STU Bratislava, Slovak republic. (in Slovak), 1999. [8] J. Flochová, M. Dányiová, “Program Solution of Supervisory Control in Windows 98/NT Environment”. In: 4 th International Scientific - Technical Conference Process Control 2000. Kouty nad Desnou, Czech Republic, 2000. [9] B. Frankovič, B at al., 2005, “MARABU Multiagent Support System for Modeling”, Control a Simulation of Dynamic Systems. AT&P Journal 4/2005, Bratislava, Slovak Republic, pp. 57-59. (in Slovak)
