It's shop floor, then top floor, for growth of Web services

Most of the buzz around Web services is the potential for linking up companies that want to engage in e-commerce. But some industry experts believe Web services could show their true value faster on shop floors than at the enterprise level.

One of those experts is Ron Sielinski, Microsoft's senior technical strategist for manufacturing solutions. "Creating Web services that can work at the shop-floor level is more demanding," Sielinski says, "but there are reasons to believe that the use of Web services could take off faster at that level."

The challenges of building Web services for shop-floor use have to do with the volume of data typically passed between plant-level applications, as well as the need for that data to be passed instantly. "The volume of data passed on the shop floor is much higher," Sielinski explains. "Also, when you are passing data between enterprise applications, you could wait minutes, hours, or even longer for that data to be transmitted. Shop-floor systems need millisecond response times."

At the same time, Sielinski notes, the type of data shop-floor systems handle is easier to package into Web services. "On the shop floor, you are typically dealing with clearly defined messages—whether a switch is on or off, or the temperature inside a vat. At the enterprise level, you're passing things like purchase orders and invoices, and it's a little more difficult to get different companies to put those in a standard format."

Sielinski also argues shop-floor system vendors are better positioned than their counterparts at the enterprise level to promote widespread use of Web services.

"If you look at the major vendors in the shop-floor automation space—such as Honeywell, Siemens, Rockwell, and Invensys—they all adhere to OPC specifications when building their products," he says. "So you already have a single voice that could have a large influence on unifying that market around Web services."

In fact, Sielinski sees the OPC's announcement that it is moving toward a single architecture, enabling all automation vendors to connect their systems to other applications, as the potential first step toward the widespread use of Web services on the shop floor.