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ABSTRACT
Manufacturers have long wished for a tool that would permit remote monitoring and control of manufacturing operations. The combination of the
Java programming language with the worldwide reach of the Internet now promises a solution to this problem. Java’s scalability, portability, and platform independence allow remote monitoring and control applications (“applets”) to run on any web browser.
Java applets eliminate the need to build custom hardwardsoftware when implementing remote monitoring and control systems. Any browser can be configured to display graphical representations of the plant or process and to annotate the image with real time data; thus, any Internet-enabled computer is a potential control station (assuming security concerns are satisfied). This gives rise to the concept of
“virtual engineers” or “remote engineers” who, armed with real-time plant information, can optimize machine setting or process control parameters, and troubleshoot problems before they escalate.
I. Background of Java in Manufacturing
Since the 1980s, modern manufacturing has seen many changes. Facing a surge of inexpensive, high- quality imports, manufacturers discarded mass production formulas in favor of just-in-time (JIT) inventory management, zero defect manufacturing programs, focused factories, electronic data interchange (EDI), and concurrent engineering product design initiatives. These new manufacturing methods brought a new world of choices and challenges not only to the manufacturers, but also to the engineers who now need to manage vast amounts of information and data simultaneously. In fact, the problem of how to control and utilize this information effectively has become more crucial than ever before [Sun97].
The emergence of the Internet has fundamentally changed the way that people communicate and view the world. The Internet has provided a universal pipeline for distributing information anywhere, anytime; the World Wide Web now permits information to be displayed (numerically and graphically) on any client platform. Using real-time data transmitted over the Internet, operators can rapidly optimize machine settings or process control operations, troubleshoot problems before they escalate, and leverage expertise that may exist only at a remote site.
To date the Internet has not been extensively used in industry because it has been neither economical nor practical to extend PC-based humadmachine interfaces (HMIs) over the totality of the entire plant.
Successful Internet-based communication tools need to have the following characteristics [Agra98]:
Interactive. The application must let users manipulate (not just view) information interactively, as is commonly done with desktops. Frequent transactions between the client (desktop) and server (source of information) are not appropriate for highly interactive users.
Platfarm independent. Users will no longer be forced into purchasing one brand of hardware or software. Successful systems must operate on a multiplicity of platforms (hardware and operating system).
Lightweight. The user application should run with a small footprint, requiring neither large nor expensive hardware for the client.
Compatible. The application must not force abandoning legacy systems or the adoption of foreign software.. It must be compatible with existing WWW cliendserver hardware, software, and user interfaces.
Java programming is a partial solution to the problem of fielding an interactive, platform independent, lightweight, compatible system.
Launched by Sun Microsystems only a few years ago, Java boasts over 700,000 program developers
0-7803-5735-3/99/$10.00 IEEE
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worldwide. While first-generation web applications displayed rudimentary views of static data retrieved from documents or databases, Java computing allows real applications to be deployed from within the browser-based environment.
Java applications, once written, can run on any
Java-enabled platform, thereby minimizing the time, effort, and energy needed to support the fielded system. New platforms and legacy systems can run the same Java software without first mounting a porting effort. Corporations can now mix hardwarehoftware environments (e.g., Widdows- based PCs, Unix workstations, Macintosh, network computers, Linux-based P O ) .
End users can access Java applications on demand via the network from any platform at any location.
Remote sites, dial-up users, and expert consultants can all run Java applications without complicated software installation, lengthy downloads, or loss of functionality. The standard web browser interface user-friendly enough for novices while at the same time being sufficiently powerful for experienced professionals.
Java is particularly well suited for lightweight clients and access-on-demand applications. Unlike conventional client-side technologies, Java applets do not require permanent disk space for installation on each machine. Java applets and applications have a small footprint that loads quickly, even over slow network connections. Whereas native C or C++ applications can be too bulky to make remote access practical and too resource-intensive for legacy desktop systems, Java programs have many high- level features (such as networking and a graphical user interface) embedded in the installed Java virtual machine; these features are then reused by each Java application.
Distributing new software updates can be challenging. Java eases that administrative burden considerably because Java is already an integral part of the web browser already present on most desktops.
New Java-based programs do not introduce new configuration, resource, or compatibility issues and do not require new administrative and maintenance effort for each new machine. Java’s portability eliminates the need to maintain separate versions for each different application platform.
In summary, Java’s scalability and portability make it a prime candidate for industrial process monitoring and control, with these known advantages:
Java extends HMI capabilities to machine (or
‘areas of a plant) where it is cost-effective to install a PC or dedicated display. All the engineers in an entire plant can have access to the same real-time data. In advanced situations, plant
staff can carry monitoring and diagnosis applications on hand-held, wireless,
Java-enabled personal digital assistants.
Java simplifies remote monitoring in several ways. Its platform independence allows it to run on any web browser, while its runtime deployment mode eliminates the need to configure remote clients.
economical use of bandwidth allows Java applets and data to traverse even standard modem and wireless connections.
Java-based alarm broadcasts are simpler to maintain than hard-linked supervisory control signals. Java alarm applications can take advantage of web-based “push” technologies to automatically convey the alarm information to the most appropriate recipient.
With this background understanding of Java’s inherent capabilities, we are prepared to ask who is using Java over the Internet, and what can engineers do with this powerful new capability?
11. Electron Microscope
Researchers at Oak Ridge National Laboratory developed Java applications to enable remote and secure operation of scarce scientific instruments such
electron microscopes (www.ornl.gov/ORNL
scientist sends his sample to ORNL where a technician places it on the scope. The scientist runs his experiment remotely using the provided Java applets. The scientist has real-time control of sample movement, focus, and magnification, Each time the user changes a parameter, the microscope supplies a 256x256~8 gray-scale image that is displayed on the user’s browser. At any time the user can download a full- save it locally. This interface allows authorized users anywhere in the world to access these unique resources.
Fig. 1
shows the Java-created control panel for the
ORNL electron microscope. The controls allow the user to shift the sample in any direction, adjust the at low or high resolution.
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111. Telemicroscope
In their paper in Nature, Wolf et al. [Wolf981 describe a Java-based cliendserver system for a telemicroscope. A computer controls an automatic microscope mounted with a CCD camera and frame grabber; it also functions as an Internet server. The microscope server receives microscope operational commands and requests for images, executes the commands, extracts the images and converts them into JPEG-compressed image files, and distributes those files to telemicroscopy clients. The user can move the microscope stage, change the magnification, and execute other microscope operations by pressing the related buttons on the client’s user interface. Java enables the efficient distribution of tasks between the server and client, thus minimizing the need for Internet communications.
1V.Hubble Space Telescope
Java technology has been used to reengineer the
Hubble Space Telescope’s Control System Center
[Rifk97]. The Graphics User Interface (GUI) completely unifies the displays on different workstations, and allows user to browse monitored data remotely. By employing this technology, a reduced staff of geographically dispersed mission engineers and mission specialists, coupled with a small on-site staff, are able to operate the Hubble
Space Telescope from anywhere.
Fig. 1.
Java-based Control of Electronic Microscope
V. Telerobotics
In the field of remote robotics, Java offers a new dimension for industrial systems. W. Kuchlin et al. in [Kuch97] demonstrates “HighRobot”, an open, workstation-based, robot control system utilizing the
Internet. The robot arm can be controlled by running a Java applet on a remote system. The network functionality of HighRobot is especially suitable for such applications as telemanipulation, telemaintenance, and telemonitoring. Java permits the delivery of real-time data such as production quantities, costs, and performance, and the Java- based GUI runs on arbitrary remote platforms.
Standard software components can be integrated into industrial process control systems, resulting in a high degree of software reusability, rapid
- project realization, and reduced cost.
VI. Unimation Puma Robot
DePasquale, Lewis, and Stein developed a Java- based application to control a Unimation Puma 760 robot for the task of painting on canvas [Depa97].
The user paints on a “virtual canvas” using a mouse or other controls; the Java-based interface program transmits the commands to the robot which manipulates brushes and paint to draw on an actual canvas. Brush holders and paint jars are mounted within reach of the robot, and two live color video images provide the user with immediate feedback of the visual results.
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Web Sewer
Java-capable Web Browser at Remote Client
Unimation Puma 760
DEC LSI23/11
Robot Controller
This system is shown diagrammatically
in Fig. 2.
The authors report that they found Java to be quite useful in the development of interactive interfaces for telerobotics. They believe that Java’s portability and robust support for multithreading, graphics, and communication make it highly suitable for remote control applications.
VII. Pharmaceutical Reactor
Sun Microsystems and Cyberonics demonstrated a next-generation open control system in which a batch fermenter, controlled by a Siemens PLC, was in turn controlled by a Sun JavaStation network computer
(http://www.sun.co.uk/ press/releases/sun359.html).
The Java application controlled the temperature, pH, and dissolved oxygen content of the mixture inside the fermenter. This experiment demonstrated that
Java worked with legacy systems, provided flexibility and extensibility when configuring systems, and reduced equipment and administrative costs, and supported remote viewing and control.
VIII. The WAVE (Web Access View Enabler)
Westinghouse Process Control has developed a web browser-based product that lets users view real- time system data including process graphics, trends, historical information, and process data
(http://wpcd.wec.comf). WAVE leverages Java an
Internet access in that, other than a browser, no specialized software is needed on the viewer’s
Fig. 2.
Telerobotic Control System computer. Westinghouse adds a new computer to the plant control system that provides a gateway to the
Internet. This machine responds to the browser’s requests, interfaces with the plant’s data highway, and supplies process data to the browser.
IX. Web@ aGlance
This product, developed by Intuitive Technology, lets process professionals use web browsers to view live process data over the Internet [Bast971
.htm). Java technology is used to deliver live process graphics screens from DCS, HMI, SCADA, and other process applications. The product includes a Java
VCR that allows the creation and replay of historical data in an animated environment.
X. Virtual Spectrometer
Distance education is another field where lava has been successfully employed. Dorneich and Jones
[Dorn97] developed the “Virtual Spectrometer,” an interactive Java-based simulation and tutoring system for nuclear magnetic resonance (NMR) imaging. The
Virtual Spectrometer (VS) re-implements existing simulation software in Java, then provides the mechanisms for collaborative learning. Its user interface is a generalization of the interfaces provided by commercial NMR machinery. It teaches operational procedures in a safe, simulated environment that allows exploration of theoretical
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Figure 3.
Virtual Factory for Ethylene Production concepts. Mechanisms are provided to allow collaborative interaction and peer tutoring. Students have the options of switching between “Observe
Expert” and “Act as Apprentice” modes of operation.
XI. Second-Best-to-Being-There fractionator, quench tower, drier, demethanizer, acetylene converters, and ethylene fractionator (see
Fig. 3). Eight key parameters (temperatures, pressures, and flow rates) were monitored in real time for each of three subsystems. The factory simulation system is located
1 .unixlab.virginia.edu/-j14f/. at http://sparc20-
Bhandari and Shor [Bhang81 developed “Second
Best to Being There,” a Java-based distance learning application that allows a remotely-located user to conduct experiments in a control engineering laboratory. The user operates on any computer platform that supports Java, and a live video stream permits viewing of the experiment and provides regular status information to support a remote lab presence. A shared whiteboard is available for collaboration with any number of simultaneous users.
XII. Factory Monitoring
To show that Java technology works as advertised, we designed a Virtual Factory - a simulation of a continuous process ethylene plant with gasoline
The user interface is an animated flowchart that presents a realistic appearance of the ethylene production process. Users can view the flow direction and click on images of equipment that they wish to monitor or control. For example, clicking on the gas fractionator reveals a 3-D image of that equipment along with a menu that permits monitor, control, or track trend data. The monitor feature shows the current values of the process parameters, updated once per second. The control features allow the user to force the setting of a process parameter.
The analysis feature tracks the value of a process variable over the past 25 minutes.
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Figure 4.
Real-Time Monitoring and Control of the Gasoline Fractionator
Fig. 4
shows the ,schematic of the gasoline fractionator. The upper window shows real-time data monitoring for five flow rates, one pressure, and four temperatures. The lower window illustrates how a plant operator can set process control variables.
XIII. Barriers to Acceptance
One obvious barrier to acceptance is a general unease about whether data can be transmitted securely over the Internet; there will be no enthusiasm for the advantages of Java if the data it transmits are easily stolen. A second issue is user authentication; no company will adopt Internet-based monitoring and control if it thinks that the general public (or competitors) can observe processes that are intended to be proprietary. A third issue is system response time. Clearly, transmission of data and images over the Internet does take time, and thus control loops have to operate over time frames of seconds rather than milliseconds as would be more typical of a hardwired control system. Yet another issue is the basic fact that Java programming is still computer programming, a skill not yet universal. At least for the next few years, monitoring and control systems will be implemented by skilled Java programmers, who may or may not be the control system designers. As befits a new discipline still in its infancy, industry decision makers are likely to be conservative and to adopt Java-based solutions gradually. Monitoring applications will far outnumber control applications until the fundamental issues of data security, user authentication, and response time improvement have been solved.
XIV. Conclusions
Java promises a revolution in the area of remote monitoring and control. Java’s advantages are that it is interactive, platform independent, reusable,
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lightweight, compatible with existing web browsers and servers, and efficient with its communications.
Engineers, managers, operators, and consultants need not be physically proximate to the controlled process; indeed, they may be geographically distributed and still see the same real-time data describing the process. As we have seen from these examples of remote control of electron microscopes, telemicroscopes, telescopes, phqmaceutical reactors, spectrometers, etc., the use of Java, while still in its infancy, will dramatically enhance our ability to see, understand, visualize, optimize, and improve remote processes.
References
[Agra98] Agranat, I.D., “Engineering Web
Technologies for Embedded Applications,” IEEE
Internet Computing, 2(3), 40, 1998.
[Bast971 Basta, N., Chemical Engineering, pg. 145,
March 1997.
[Bhan98] Bhandori, A. and Shor, M.H., “Access to an Instructional Control Laboratory Experiment
Through the World Wide Web,” Proceedings of the
American Control Conference, pg. 13 19, 1998.
[Depa97] DePasquale, P., Lewis, J., and Stein, M.,
Telemanipulator and Telepresence Technologies, 4,
159, 1997.
[Dorn97] Dornich, M. C., and Jones, P. M., IEEE
International Conference on Systems, Man, and
Cybernetics, 1861, 1997.
[Kuch97] Kuchlin, W., et al., IEEE 6fi
Conference on Emerging Technologies and Factory
Automation,-115, 1997,
[Rifk97] Rifkin, A., IEEE Internet Computing, 1(3),
28, 1997.
[Sun971 Sun Microsystems, “Java in manufacturing:
The Momentum Builds,” 1997.
[Wolf98] Wolf, G., et al., Nature, 391(5), 613, 1998.
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