OI Software Opens a Window To the World Wide Web
You're relaxing at home on a Sunday afternoon, a favorite beverage in one hand, the remote control in the other. Suddenly, your pager goes off. You think to yourself, "Oh no, not another weekend afternoon spent chasing an emergency at the plant."You log into your home computer to read your e-mail.
You're relaxing at home on a Sunday afternoon, a favorite beverage in one hand, the remote control in the other. Suddenly, your pager goes off. You think to yourself, "Oh no, not another weekend afternoon spent chasing an emergency at the plant."
You log into your home computer to read your e-mail. Embedded in the message is a URL field that allows you to pull up a plant display detailing the problem. With your web browser, you're able to acknowledge the alarm, troubleshoot the failure, and take corrective action without ever leaving your driveway.
Sounds too good to be true? In fact, Schneider Automation (North Andover, Mass.) demonstrated this simple scenario at a recent industry trade show, using Java code, browser-based operator interface software, and a Lotus Notes server driven by automation system events.
Schneider is one of several vendors pioneering Internet technologies on the plant floor. One of the most exciting opportunities is the use of web browsers in operator interface software. (See box on the fourth page of article for summary of benefits.)
Gimmi Filice, product manager for Total Control Products/Taylor Software (Edmonton, Alberta, Canada), discusses two capabilities of Web-aware OI software. "The first is access to a worldwide 'wire' that can be used to transfer data. The second is the rich Internet environment for presenting data from various sources."
Users benefit from Internet wiring because it lowers the cost of monitoring remote sites. Taylor's fxView OI software, part of its FrameworX series, can access remote sites over Internet's TCP/IP. As well, the Internet development environment leverages Java, ActiveX controls, and HTML to create rich displays with a minimum of client overhead. (See "Internet Definitions" box for summary of terms.)
"The Internet is driving a need for interoperability among user applications," says Steve Rahr, Plantscape marketing manager for Honeywell IAC (Phoenix, Ariz.). "This will carry over into standards for process control, such as OPC (OLE for Process Control). Eventually, users will be able to select best-in-class process control functions from multiple suppliers and expect them to work together seamlessly."
Honeywell has leveraged commercial Internet standards in its recently announced SafeBrowse, an integrated web browser for the PlantScape hybrid process control system. SafeBrowse allows users to display HTML documents as ActiveX components within the control window, without obscuring critical views such as alarm information.
Push me, pull you
Another benefit of the Internet is its use of "push" technology. Simply put, push technology automatically displays and changes data in your web browser based on your application's preselected parameters.
Chris Meunch, WinCC development coordinator for Siemens Energy & Automation (Alpharetta, Ga.), comments, "The Internet currently has the notion of a pull mechanism. Every time a screen needs to be refreshed, the operator has to do it manually. But because the web is moving to push technology, our goal is to show exactly the same information on the browsers as on the proprietary front ends." A new user interface for WinCC will be based on the Internet Explorer 4.01 using Dynamic HTML.
FIX Broadcast Network is Intellution's (Norwood, Mass.) push technology for its FIX family of automation software. It utilizes ODBC (open database connectivity) to gather information from FIX real-time and historical data, or from any ODBC-compliant database such as Microsoft's SQL Server, SAP R/3, or Sybase.
Intellution product manager David Mills believes the real benefit of the web-aware software is that operator interfaces can be configured from a single point at the server. All clients are thin clients, requiring only an Internet browser.
Ci Technologies, Inc. (Fairport, N.Y.) implements the client/server architecture of its Citect for Windows to send data changes over the Internet. As shown in the diagram (last page), the application database is loaded on the client. At startup, the client updates its database from the server. During runtime, the client receives data changes from the server.
Using the web with embedded diagnostics is a benefit in VLC control software from Steeplechase Software Inc. (Ann Arbor, Mich.). A Diagnostic Wizard in the PC-based flowcharts generates diagnostic logic and messages, and calls a URL address for web access to repair instructions.
Control Technology Corp. (Hopkinton, Mass.) is installing an interesting remote diagnostics application at a consumer products manufacturer. Web server technology is embedded in CTC's machine controllers. Java applets serve up display, diagnostics, and soon, documentation information for the machine-control application.
Beyond benefits to components
Benefits for web-aware operator interface software can be summarized:
Location independence—remote monitoring;
Function independence—access any device through its URL;
Ease of use—leverages familiar tools;
Access to information—anywhere, anytime and;
Reduced costs—client/server architecture and Internet/intranet wiring.
Additional cost and performance benefits can be gained through the use of thin clients in the automation architecture. Thin clients rely on servers to maintain the application, real-time database, and historical database. The client runs a "slim" version of the display software and receives real-time data updates over the Internet or intranet. To paraphrase, thin clients look great; are less filling.
The Internet's client/server architecture of distributed computing and thin clients is evolving with new object component models. The debate over which component model to choose seems eerily familiar.
Similar to the operating system wars (Windows vs. Unix) and the browser battles (Netscape vs. Internet Explorer), the component model clash pits Microsoft's COM (component object model) against Sun Microsystems' JavaBeans component model. (See "Internet Definitions" box.)
Microsoft's ActiveX components, based on COM, implement small units of code that run in a container application to provide features such as connection to a remote database or display.
Sun's JavaBeans uses the Java programming language to develop reusable applications that can run on any hardware platform.
The two systems differ in complexity, security, and application development. However, recent announcements by Sun and Microsoft are making many of these differences moot. Suffice it to say that, for now, ActiveX is platform-specific (32-bit Wintel) and Java is language-specific.
Much more on this discussion is available in the general computer magazines and on the Internet. (Search www.techweb.com.) Here, the focus is on which models the operator interface software vendors are implementing, and why.
Java vs. ActiveX
Standing firmly in the Java camp is PC Soft International (Braintree, Mass.) with its just-released Wizcon for Internet . Says Internet product manager Noam Sadot, "An important target was to provide the same performance as a traditional SCADA system. We optimized the Wizcon for Internet server to run on Microsoft Windows NT and send event-driven updates to client stations via TCP/IP sockets."
Java was chosen to implement operator interface components because, "Java opens the choice for client platforms to include Microsoft Windows 3.11, network computers, TV set-top boxes, and Macintosh and Unix workstations [in addition to Windows NT and Windows 95]. All of the above do not support ActiveX. Also, Java applets tend to be smaller than their equivalent ActiveX controls, which can shorten download time."
Schneider Automation built the display example cited at the beginning of this article with Java. A process mimic display was entered in the form of a Java applet, and animated with Java routines which implemented the Modbus/TCP protocol.
Another Java supporter is The Foxboro Company (Foxboro, Mass.), which implements Java in all of its web-based user interfaces. For example, FoxSPC.com uses Java for visualization of on-line displays of statistical process control charts. Java is important to Foxboro's I/A Series cross-platform strategy.
In the ActiveX camp is Iconics (Foxborough, Mass.) with its just-released GraphWorX32 ActiveX container. The software interfaces to applications through OPC and can act as a container for ActiveX controls from Iconics or third-party developers. Says vp Chris Kellogg, "The GraphWorX viewer may be embedded in an HTML web page, a Visual Basic or C++ application, or any other ActiveX container."
Iconics has chosen ActiveX over Java because "our belief is whoever gains control over the Internet browser market will control the object technology. Recent market data…indicate the war may already be decided. Iconics has selected the Microsoft COM model."
Mike Santori, marketing director, National Instruments (Austin, Tex.), adds, "ActiveX technology provides an unprecedented method for software developers to take advantage of existing code. By providing ActiveX controls, such as National Instruments' ComponentWorks products, companies can build shareable components to be used in any container environment. By providing ActiveX containers, companies can incorporate controls from different manufacturers."
National Instruments offers an Internet Developers Toolkit for its software applications, such as BridgeVIEW. Users can view displays on the web and program the application to send e-mail messages and FTP (file transfer protocol) data files based on events.
Under development at TA Engineering (Moraga, Calif.) are web access tools for its AIMAX system. TA Engineering choose to develop in ActiveX "primarily due to the way data flow is handled. For an ActiveX arrangement, the majority of the code is on the web server. The view computer can be a relatively dumb terminal and would not require a long download to set up a monitor site."
Two of the early entries into web-aware software are the Scout browser from Wonderware (Irvine, Ca.) and the WebClient from USDATA (Richardson, Tex.). Both packages previewed at the ISA/96 trade show, in October 1996. Wonderware's Scout, implemented on COM and ActiveX technologies, allows InTouch users to view live industrial data over the Internet or intranets.
USDATA's WebClient, which runs on Windows 95, NT, or inside Microsoft Internet Explorer, is a thin client (presentation only) to the FactoryLink ECS server, which manages data collection and maintains application logic and graphics. Says Mike Chandler, director of product marketing, "We believe the cost of ownership of Internet Explorer-based clients will be comparable to NCs [network computers], while still providing the Windows-based computing benefits that NCs lack."
While the Internet will make information available to remote users, there are some concerns about its use in high-density, hazardous applications. Says David Bachman, product manager for ABB Industrial Systems (West Henrietta, N.Y.), "It is unlikely that personnel will be allowed to perform control commands over the Internet in large, concentrated, or hazardous applications because of risk issues. End-users will be given access to services on the company's intranet or over the Internet because software management [at the user end] is simplified or minimized."
ABB's Advant Enterprise Historian includes a web server for Internet or intranet access. Security is controlled by the Advant OCS (open control system) and through the plant's intranet firewalls.
Dan Benson, vp Ann Arbor Technologies (Ann Arbor, Mich.), believes that intranets, not the Internet, will dominate plant web architectures. Ann Arbor has developed an industrialized web browser, suitable for plant-floor use.
Also leveraging enterprise intranets is Fisher-Rosemount (Austin, Tex.). Internet Explorer browser software on clients communicate with the intranet server (through appropriate firewall security) via smart web pages from Fisher-Rosemount. The F-R software links to OPC and ODBC servers.
In addition to security, other issues of concern to users of browser-based OI software include:
Internet performance and latency;
Bandwidth limitations; and
Adds Andy Halarewicz, product specialist with Elsag Bailey Process Automation (Wickliffe, O.), "There are total cost of ownership issues, such as licensing and how to keep all clients synchronized. With various applications appearing on different machines, reliability and performance can be affected." Elsag Bailey's Process Information Web Server, part of the Symphony enterprise control system, delivers Java and ActiveX technologies to the client desktop.
"The broad source of ActiveX and Java components is a double-edged sword," warns Mark Davidson, Foxboro's strategic marketing director. "On the positive side, users have a wide choice of operator interface components. On the negative side, users are responsible for robustness, security, and performance when they mix-and-match software objects."
Despite these concerns, there is no argument about the vast impact the Internet and its development tools have had on industrial software. From the browser-enabled client in Chicago that views a display in Australia, to the embedded HTML tools in a diagnostic flowchart, the Internet continues to improve user interface.
"Does this mean that the days of the traditional HMI [human-machine interface] software are numbered?" asks Benson Hougland, director of technical marketing, Opto 22 (Temecula, Calif.). "With leading vendors moving their development environment to an object container, how is that so different from a browser? Opto 22 provides data in a universal manner that can be employed to the user's discretion." For example, the OptoServer, an OPC server, provides data at a user-defined rate. An ActiveX object in a container, such as a browser, receives and displays data in an HTML page.
The Internet and its underlying, ever-improving development environment will have an immediate and positive impact on industrial operator interface. The benefits of web-aware software, and the rich Internet development tools, are too important to ignore. Users of this technology, however, need to be aware of its limitations before haphazardly applying its advantages. It's one thing for your Internet connection to crash while you're helping your son with his homework. It's an entirely different thing when you're running a power plant.
ActiveX control: Software modules based on Microsoft's COM architecture, ActiveX controls add functionality by calling ready-made components into a program. On the Internet or on an intranet, ActiveX controls can be linked to a web page and downloaded by an ActiveX-compliant web browser.
COM and DCOM: Component Object Model (COM) is Microsoft's component software architecture. It defines a structure for building program routines (objects) that can be called up and executed in a Windows environment. COM provides the interfaces between objects, and Distributed COM (DCOM) defines the remote procedure call (RPC) which allows those objects to be run remotely over the network.
HTML: HyperText Markup Language is the document format that defines a web page's layout, fonts, graphic elements, and hypertext links to other sites.
Internet: The Internet is a large network made up of a more than 100,000 interconnected networks in over 100 countries. Originally developed for the military, the Internet has become a worldwide information highway.
Intranet: An intranet is an in-house web site that serves the employees of the enterprise. Although intranet pages may link to the Internet, an intranet is not a site accessed by the general public.
Java: Java is a programming language for Internet and intranet applications from the JavaSoft division of Sun Microsystems. Java was modeled after C++ and designed to be hardware-platform independent. Java programs can be called from within HTML documents or launched stand alone.
JavaBeans: Sun's component software architecture (compare to COM), JavaBeans are independent Java program modules that can be called up and executed or run remotely in a distributed computing environment.
OLE and containers: OLE, a compound document technology based on COM, allows an object to be embedded or linked into a document, called the container application. (A web browser can be a container.) When the object is double clicked, the application that created it, called the server application, is launched.
OPC: OLE for Process Control is an emerging software standard designed to provide access to industrial data through a robust, high speed communication infrastructure.
TCP/IP: Transmission Control Protocol/Internet Protocol is the communications protocol of the Internet. The TCP part ensures that the total amount of bytes sent is received correctly at the other end. The IP part provides the routing mechanism.
Thin client: A "thin processing" client in a client/server environment processes only keyboard input and screen output. All application processing is done in the server.
Web browser: A web browser is the program that serves as your front end to the World Wide Web on the Internet. To view a site, you type its address (URL) into the browser's Location field.
EXCLUSIVE: Active Displays Provide Single Database Solution
In a perfect world, tag databases do not have to be reentered, or projects duplicated, to run multiple machines. In a perfect world, once a piece of data is entered, it is available to all users of the information. In reality, multiple runtimes frequently require multiple tag databases.
Rockwell Software (West Allis, Wis.) implements Internet technology to provide its RSView32 HMI software with a client/server architecture and single tag database support. The Active Display System is an RSView 32 add-on software option for distributed clients, which can both monitor and control (through appropriate security) the server application. It uses a single project with a single database. Changes to the project are immediately available to the clients.
Active Display System is comprised of the Active Display Server and two client options—Active Display Station for dedicated users and Browser for remote users. Multiple clients can access multiple servers. Version control software ensures that servers and clients are always using the current version.
The Active Display System embeds Microsoft and Internet technologies, such as DCOM, ActiveX, and VisualBasic, for client/server communications without recompiling code. ActiveX and VBA are key to Rockwell Software's technology track of a single operator interface architecture, from hand-held thin clients through distributed client/server.
Key Benefits of Web-aware Software
Location independence: Plant-floor displays with live data are available to any browser-aware client—in the factory or around the world.
Function independence: Operator panels do not need to be preloaded with device-specific software. The OI only needs to know the URL of the device being monitored.
Ease of use: Browser-based operator interfaces reduce user learning curves and speed application deployment.
Access to information: Web browsers leverage standard tools to provide any application with access to a wealth of data.
Reduced costs: System costs are lowered through the use of Internet wiring, thin clients, and ubiquitous display tools.
Source: Schneider Automation and National Instruments