Maintaining a smooth flow of information from one software application to another needn’t be quite the hassle that it once was during upgrades. Just ask the automation engineers at Chevron Global Lubricants, the San Ramon, Calif.-based manufacturer of greases, oils, and other blended lubricants. As they discovered, a new generation of markup languages can streamline software integration by defining data structures for deploying the extensible markup language (XML) in manufacturing.

Chevron’s engineers learned about the power of incorporating these languages directly into their code when they embarked upon a worldwide modernization program. The multiphase plan was to replace a range of disparate control schemes, manufacturing execution systems (MESs), and enterprise resource planning (ERP) systems with common platforms.

Implementation of the plan would begin at the company’s plants in Port Arthur, Texas and Richmond, Calif.  Chevron would first replace the control systems at these locations with the same distributed control system (DCS), one that adheres to the ISA88 batch-control standard promulgated by the International Society of Automation (ISA) ( www.isa.org) in Research Triangle Park, N.C. In the next phase, it would install a standard ERP system. Until then, the new DCS from Yokogawa Corp. of America ( www.yokogawa.com/us/) in Sugar Land, Texas would have to communicate with the legacy ERP system through the old COBOL-based interface.

To establish a new communications interface that would not have to be rewritten a few years later, Chevron took the advice of Yokogawa’s experts and adopted the Business-to-Manufacturing Markup Language (B2MML). The WBF ( www.wbf.org)—the Organization for Production Technology based in Chandler, Ariz.—developed this standard to implement in XML the data models specified by the ISA95 family of enterprise-control system standards. By defining common data structures, B2MML links business-level systems like ERP software with manufacturing systems like DCSs and MESs.

Using B2MML, Chevron was able to convert the old ERP transactions into XML messages that the new DCS can decipher. Not only did the standard simplify this initial integration, but it also made provisions for integrating the new ERP system later. It also makes maintaining the interface easier. Messages can be used for more than one production process, and adding new data into existing messages is possible without a major redesign.

Chevron is not the only company finding that markup languages can simplify and shorten integration, which can easily cost more than the software itself. “When B2MML was originally released, we had companies that were spending anywhere from one to two years integrating their business systems with their shop-floor MES systems,” reports Dennis Brandl, president of BR&L Consulting ( www.brlconsulting.com ) in Cary, N.C. and editor for WBF’s B2MML committee. “Once the standard was in place, those things were happening in about two months.”

Implementing industry standards

B2MML and other markup languages can streamline software integration because they define data structures according to the industry standards for the application at hand. Right now, the most popular ones in manufacturing are defining these structures in XML. In the case of WBF’s markup languages, B2MML uses the World Wide Web Consortium’s XML schema definition (XSD) to implement the ISA95 standard for exchanging information between business and control systems. WBF’s BatchML uses XSD to implement the ISA88 standard for batch control systems.
To help users visualize the relationship between standards and XML, Brandl compares markup languages with ordinary human languages like English. In spoken languages, a voice transmits a message according to the rules of the language. In the case of markup languages, XML is analogous to the system of sounds generated by the voice, and the markup language is analogous to any spoken language.

Like every spoken language, each markup language contains a set of rules and conventions, but these rules define data tags. “When you get right down to it, XML files are simple text files,” explains Brandl. “XML puts well-defined tags on each piece of text so you know not just what the data are, but what they mean.”  These tags fit together in a well-defined structure that Linux, Windows and Unix systems can interpret.”

Because the rules of individual markup languages are industry standards, each language is really an implementation-ready format for a particular standard. It, therefore, is much easier for an operating group within a company to enlist the help of the information technology (IT) department in moving data. While IT may not understand a 100-page manufacturing standard, it will know how to organize data based on XML, notes Dave Emerson, director of Yokogawa’s U.S. development center and chairman of WBF’s ...