Java Object Technology Can Be Next Process Control Wave
Like a surfer seeking that perfect wave, today's control engineers are searching for the "technology wave" to take their process control systems into the next millennium, and meet mounting information technology (IT) challenges. Control engineers sometimes face their corporate IT counterparts across a chasm of incompatible requirements.
Like a surfer seeking that perfect wave, today’s control engineers are searching for the “technology wave” to take their process control systems into the next millennium, and meet mounting information technology (IT) challenges. Control engineers sometimes face their corporate IT counterparts across a chasm of incompatible requirements.
Corporate IT wants data from factory floor systems to feed enterprise applications and wants the factory to run its applications on “open” systems. The push from enterprise IT sometimes can force or encourage replacement of reliable, proprietary PLC-based systems with “soft’ PLCs and PC-based control. Beyond the often-debated issue of PC reliability, the cost of these re-architected factory solutions, including not only the purchase of new hardware and software, but also training and maintenance costs, is not insignificant.
Even more importantly, factory engineers need better reliability than the corporate system may offer because they deal with issues of safety and loss of life. They like what PC-based soft control can do to make lives easier with its standardized communication protocols and nice, graphical interfaces, but they have doubts about business- or safety-critical reliability in many situations.
The Java technology platform offers a solution to meet the needs of enterprise IT with less disruption to the existing factory environment. With this approach, factory managers can extend the useful life of investments, have much more choice about when and whether they change from existing control solutions, yet still deliver data to fulfill both factory and corporate requirements.
Power of Java
The true power of Java technology can be found in software “objects” (small pieces of data and programming code encapsulated for use in a program). The Java event model means Java objects have “wheels” on a network. When a Java object is created, it already knows where it came from, that it’s on a network, and what its function is. Upon creation, the object registers itself to the network and will be automatically delivered to any address that needs it.
Using the Java language and component model, control systems can publish data in formats usable by any platform, anywhere in the company. The data that today typically comes out of factory controllers in the form of tag files can be “wrapped” inside objects and made available to any client that has permission to read them, anywhere on the corporate network, or even to suppliers and partners on the “extranet.”
For example, say a design engineer’s Unix-based workstation needs data from a factory system run by a Schneider Automation
Modicon PLC (programmable logic controller). Information from the factory system can be wrapped in an object written in the Java programming language, and seamlessly and efficiently sent to the workstation, ready to be published or included in usable formats, such as a spreadsheet or software quality assurance analysis package.
This strategy can be implemented in small cost-effective increments and does not require the wholesale replacement of any factory equipment. Real-time data can be communicated to both factory and corporate databases by “opening up” existing PLCs. Most PLCs today can be fitted with a TCP/IP card which allows them to talk to the factory intranet.
Data coming from the controller can be sent to a server and wrapped in objects that contain data samples (temperature, pressure, liquid level, etc.) and information (date, time, system location, alarm status, and so forth) that make the data usable to anyone with permission to see it.
Java object model value
The value of a self-describing object becomes clear when one considers the meaning of data in different situations. A temperature reading from sensor number 12 at 102 °C could be critically high for the cooling system in a nuclear reactor, or it could be too cold for the completion of a chemical process. Self-describing objects not only report the temperature, they also indicate that this is a critical temperature and, because of the Java language event model, alert the appropriate application (which could then page someone who can handle the alarm).
Benefits of this fairly low-cost and simple access strategy include:
Data wrapped in self-describing objects becomes available to the entire information systems architecture and can be pushed to the applications that need it, from the factory floor on up to corporate finance or the manufacturing planning system.
Suppliers can be given secure access to real-time data via an Internet site, allowing them to see and respond immediately to changes in quality or yields.
Maintenance and configuration management are simplified because publication of new process data and parameters can be published to a web site. Browser access to device configuration, process data, and equipment use gives plant engineers a consistent view of process and equipment performance;
Management receives faster feedback on yields and process improvement efforts with web-based utilization analysis, diagnostics, and data warehouse access;
The user process control interface can be run on any client, including network computers or scaled-down PCs, reducing the cost of factory workstations and leveraging existing investments in computer hardware; and
Investment in existing control equipment is preserved until such time as it becomes desirable to change because of factory requirements, rather than change being forced by corporate requirements.
Wrapping data in objects is the most elementary usage of this technology. Users who wish to go beyond investment protection and service extension can use Java technology to move toward a “smart” factory environment.
One of the most intriguing and promising facets of Java technology is its scalability. Many companies, large and small, are currently developing embedded Java technologies, from microprocessors that contain a “Java virtual machine” as their machine instruction set to real-time Java operating systems.
Another intriguing possibility with Java technology is the development of “intelligent agents” for control. Agents can be built to automate complex tasks in collaboration with other agents, such as maintaining and optimizing processes, watching for outliers, analyzing cause and effect, managing configuration changes, and interpreting statistical quality control charts. The compact, simple Java platform, with its complete object model, reliable security model, and built-in network awareness and event model, makes it the ideal language for developing intelligent agents to handle process control functions.
A Java technology model has already been embraced by a number of automation vendors and engineering firms for factory data viewing and control systems. Foxboro (Foxboro, Mass.) has a suite of Java technology applications, including Fox SPC.COM, for statistical process control, and DPM.COM, for dynamic performance monitoring.
Schneider Automation (Modicon, North Andover) has demonstrated a human-machine interface system running on a JavaStation network computer. It provides a flexible framework for talking to PLCs, as well as control functions for data viewing. Short term, Schneider plans to use Java technology in soft real-time control for non-time-critical processing including HMI support, communication to the manufacturing execution system, and control language support with seamless integration to a IEC 61131-3 control language.
Another committed user of Java technology is Cyberonix (Berkeley, Calif.). This consulting and engineering firm uses the Java platform exclusively to solve its customers’ enterprise-wide automation and control problems. Cyberonix has a powerful and flexible library of objects written using Java technology which they can use to develop custom, industrial-strength control systems.
In October 1997 Sun Microsystems and Cyberonix demonstrated a prototype Java technology system using a Siemens PLC with a TCP/IP interface. A pilot project system now controls a biotech fermenter at Berlex Biosciences (Richmond, Calif.).
A control application using embedded Java technology comes from Rockwell Collins Advanced Technology Center (Cedar Rapids, Ia.). The Collins group has developed a processor, the JEM1, using Java byte code as its machine instruction set. The chip can run hard real time applications because it uses a software linker to create small, preresolved JEM1 executables; features hardware support for Java threads; and employs a real-time kernel (written entirely in Java) that does not generate garbage. With the elimination of garbage generation, deterministic operation is possible with no changes to the Java programming language kernel. Rockwell Collins is using this chip as the brains of embedded avionics controllers.
Look for automation vendors in the near future to begin offering Java technology engines (either software or hardware) for soft and hard real time control embedded inside PLCs, as well as intelligent automation devices such as motor starters, intelligent sensors, and actuators.
For the control segment, Java technology is a promising new way to solve manufacturing problems that have been difficult or impossible to resolve. The Java programming language and computing environment liberates control information to move anywhere in the enterprise or supply chain it needs to go. Its scalability and rapid development capability make it the ideal platform for devices such as sensors and actuators, as well as for higher-level applications such as open control systems. It can handle both soft and hard real time operations, and can work with industry standards such as IEC 61131-3 languages. A growing number of automation suppliers are planning innovative Java technology products.
In short, Java technology will help to resolve many of the thorny issues that have become a source of controversy in control engineering over the past few years.
|Dr. Robert Atherton, is Worldwide Manager of Process Control Market Development, Sun Microsystems, Palo Alto, Calif.|
For additional object terms, see preceding cover article.
Extranet : a collaborative network that uses Internet technology to link businesses with their suppliers, customers, or other businesses that share common goals.
Intranet : a network contained within an enterprise.
Object : in object-oriented programming, small self-describing pieces of code that make up the elements of a program. An object can contain data or methods (programming procedures).
Component : a reusable program building block that can be combined with other components in the same or other computers in a distributed network to form an application. Component examples include: a small interest calculator or an interface to a database manager. Components can be deployed on different servers in a network and communicate with each other for needed services. A component runs within a context called a container. Examples of containers include pages on a web site, web browsers, and word processors. One component can interrogate another one to discover its characteristics and how to communicate with it.
Intelligent agent : a software “component” that can gather information and independently execute a task defined once without your immediate presence and on some regular schedule.
Java objects, Microsoft, CORBA
Palo Alto, Calif.— Java objects benefit Sun Microsystem partners such as Schneider Automation (Modicon, North Andover, Ma.) and Cyberonix (Berkeley, Calif.) in developing control systems. User benefits include more reliable, flexible control systems with lower development and maintenance costs.
Other object models in use include CORBA and Microsoft-based COM/DCOM, OPC, and ActiveX. (See related article.) Because Java’s programming language works across platforms, Java language users may select other object models. Microsoft-object model users, including ObjectAutomation, PCsoft, and Wonderware, also make use of Java’s programming language. Some Sun Microsystem partners, such as Schneider Automation, are experimenting with a variety of object standards.
The platform-independent nature of Java provides a broad solution for incompatibility issues among different object standards. There will be competing noncompatible standards, although interfaces between systems based on different standards can be developed.
To ensure Java object technology meets the most demanding industrial applications, users need a truly reliable computing platform, such as Sun’s SPARC Solaris systems, on which to run the software. Sound software development methodologies are needed along with a thorough security model can prevent misuse of objects. Java technology has a thorough security model.
Adoption of object technologies is occurring. Mass adoption will come within three years. The result will be integration of control technologies into mainstream IT and development of powerful, cost-effective control systems.
Virtual instrumentation ‘beans’ are certified
Los Alamos, N.M.— Used to develop Java-based graphical user interfaces for industrial and laboratory control applications, Virtual Instrumentation Beans (VIBs) single development edition from ErgoTech Systems Inc. was recently awarded a 100% Pure Java certification from Sun Microsystems Inc.
VIBs are JavaBeans used to create dynamic, real-time instrument and process monitoring displays that can be viewed remotely using any JDK 1.1 compatible Web browser. Available since March 1998, VIBs’ suite of JavaBeans components include meters, strip charts, annunciators, active input devices (buttons, knobs, sliders), and seven-segment displays. The beans are also able to connect live data sources for real-time updates with simple extensions of the package’s basic VIB Data Servers.
The product’s 100% Pure Java certification ensures VIB is portable across all Java-compatible environments and platforms; written entirely in the Java language; and certified by an independent testing center on multiple platforms.
“Complete portability of JavaBeans components combined with the strong Java platform network model makes Java technology a natural match for distributed factory automation applications,” says Jim Redman, ErgoTech’s president. “VIB’s 100% Pure Java certification assures our customers that our product’s components can be placed anywhere on the network as part of fully distributed integrated solutions running from the plant floor to the front office.”
ErgoTech also recently announced that VIBs are completely compatible with Sun’s JavaStudio, which allows users to visually construct complete user interfaces with logic and mathematical computations without any Java programming.
In addition, VIBs’ components can be used to create stand-alone Java applications or applets, or they can be used with ErgoTech’s open Java-based industrial framework to create distributed component-based software for machine control, factory automation, and enterprise-wide integration.