There is a technology, however, that is gaining ground in manufacturing software circles that promises better integration of all of these applications—Service Oriented Architecture (SOA).
Satya Narayan Sahu, solution manager of Manufacturing and xMII, at enterprise applications supplier SAP, in Newtown Square, Pa., says, “Most plant information systems were designed to run a plant, and connectivity to any other system or application was an afterthought. Until the last five to seven years, few manufacturers even mentioned that they needed the automation layer, the manufacturing execution system (MES) layer, and the enterprise resource planning (ERP) layer to be able to talk to each other.”
According to Sahu, information technology (IT) developers cobbled together direct links between differing layers of applications as a way to share data among plants within a distributed manufacturing network. But this led to a complex web of point-to-point solutions. Now, IT developers are learning from manufacturing departments, where engineers have developed standardized ways to assemble components.
“The underlying concept is enterprise service oriented architecture, which allows you to change and improve your business processes without an expensive IT integration project. With enterprise SOA, you can simply replace or add components to create new processes—the software version of plug-and-play,” adds Sahu.
Hub Vandervoort, chief technology officer of Progress Software, a Bedford, Mass., developer of SOA software tools, agrees. “Manufacturing has largely been dominated by proprietary protocols and interfaces,” he says. “That space is starting to realize that XML (eXtensible Markup Language) and similar standards are good. SOA is a way of building systems. It’s like a platform that requires a set of components and an Enterprise Service Bus. Then you must semantically integrate data.”
Not surprisingly for an enterprise application supplier, SAP has defined something called Enterprise SOA. Says Sahu, “Enterprise SOA goes beyond the fundamentals of an SOA. SOA is a distributed software model that uses independent Web services to support business processes, but the enterprise SOA approach—as defined by SAP and its partners and customers—elevates the design, composition and management of Web services through the use of enterprise services.”
The next question is what elements comprise an SOA. Greg Millinger, Workflow/SOA Product Manager for GE Fanuc Intelligent Platforms, in Charlottesville, Va., defines three components—a services bus, a repository and an adapter (or service provider). “The bus is a communications link,” he says. “You take an application, wrap the data into a ‘service provider,’ drop it on the bus and then you can put the data into the repository for the purposes of building composite applications, that is, applications built from other applications. Once the repository holds data, you can, for example, build an application for processing a production order by pulling together data from the enterprise application, then build it into a human-machine interface.”
IT departments have been doing this for a long time, according to Millinger, but manufacturing required faster data transfer than business applications. “For example, take an error-proofing application,” says Millinger. “You need to plug into the programmable logic controller or other device, take data and display it quickly for the operator to know whether the operation was done successfully.”
SOA does not necessarily equal standards. Under the hood within a custom application, the tight data flow requirements might mean a custom interface. “Exposing data to the outside world does require standards, such as standard Web services,” adds Millinger.
Gary Mintchell, firstname.lastname@example.org