And as interoperability grows and more application-to-application communications are sought, the need escalates for Web Services that do all these things.
The World Wide Web Consortium (W3C, www.w3c.org) defines them as software systems that support interoperable machine-to-machine interactions over a network. A Web Service has an interface described in a machine-processable format—specifically Web Services Description Language (WSDL), which is an XML, or eXtensible markup language, format for describing network services,” says the W3C. Other systems interact with the Web Service in a manner prescribed by its description using Simple Object Access Protocol (SOAP)-messages, typically conveyed using hypertext transfer protocol (HTTP) with an XML serialization in conjunction with other Web-related standards.
Any network supporting transmission control protocol/Internet protocol (TCP/IP) will support Web Services. And when someone says something is dot-Net—referring to Microsoft .Net—that means there is a product or solution component that will expose data to XML Web Services. “We’re beginning to see interest at the device level. It is our strong belief that XML will be the language used to communicate between computers and computer systems in the future,” says Bill Peisel, chief technology officer of networking chip maker NetSilicon Inc. (www.netsilicon.com), Waltham, Mass.
Companies have improved performance with Web Services, says Chris Colyer, industry manager for general manufacturing in the manufacturing-industry solutions group at Microsoft Corp. (www.microsoft.com), Redmond, Wash. “Cooper Tire & Rubber Co., which uses a Microsoft-based software-and-server solution, as well as XML-based Web Services, reduced time-to-market for products from two years to six months. Dell Computer Corp. is using a set of Microsoft’s e-commerce Web Services to improve its customers’ experience, reduce product returns and increase sell-through.”
To open up industrial automation, the OPC XML Data Access (OPC XML DA) specification is redefining the OPC interoperability standard around XML objects and schemas—work being based around Microsoft .Net, Peisel says. Adds Ron Sielenski, Microsoft’s senior industry-technology strategist for manufacturing, “What that (specification) means is that you now have a standardized interface for reading or writing variable information, pretty much anywhere within the operational domain. You might have a human-machine interface or SCADA (supervisory control and data acquisition) application and you want to integrate that with a manufacturing execution system (MES). If you want to track the status or availability of a particular machine, you could expose its operational state via the Web Service.”
Other exciting facets of Web Services include better connectivity, mobility and platform independence. “We can now have servers and clients on any Internet appliance supporting XML, which brings great promise for a new generation of communication. We’ll next be seeing controllers supporting these technologies natively—and there will be communication directly between a PLC (programmable logic controller) and an Internet browser,” says Rich Carpenter, manager of global solutions for GE Fanuc Automation, Charlottesville, Va. (www.gefanucautomation.com).
User-friendliness is another benefit. “Web Services make it very easy to obtain information from different computers, locations and systems without requiring the end-user to learn how to connect to the other systems,” says Renee Brandt, product manager and technical specialist for visualization products at Wonderware, Lake Forest, Calif. (www.wonderware.com).
Even with data acquisition, Web Services makes sense, says Eric June, chief software architect of AssurX (www.assurx.com), a Morgan Hill, Calif., vendor of enterprise quality tracking software. “You’re able to span across platforms. Web Services will become the predominant way of integrating disparate systems together, such as MES and ERP (enterprise resource planning).”
C. Kenna Amos, [email protected]
