But what traditional HMIs can do is changing, says John Roberts, technical specialist for B&R Industrial Automation Corp. (www.br-automation.com), Roswell, Ga. A trend he sees is demand for industrial computers with motion control and programmable logic control (PLC) functionality that also support operator interface displays. Valerie Tur, a Tampa, Fla.-based field applications engineer for Schneider Electric (www.us,schneider. com), also sees more demand for integrated HMI-PLC functionality, particularly in water/wastewater operations.
Screen size may determine a user’s choice of an HMI or industrial computer. Tur says the most popular operator interface screen size hovers around 4.5 inches diagonal. She observes that users who choose an industrial computer typically seek screen sizes at or above 10 inches. A
differing opinion comes from Ann Ke, product-marketing manager for panels and tablets at Wonderware (www.wonderware.com), an Invensys company in Lake Forest, Calif. Ke says the crossover point for choosing an IC is a 15-inch screen size. The reason people are moving to the ICs is that the computers are becoming more cost-effective than traditional operator interface displays—and that occurs at the 15-inch-or-greater screen size, Ke says.
Operator interfaces with graphics capabilities are a trend, Tur says, noting she’s seen much interest among users about developing programs with Microsoft Visual Basic for Applications. That can be accomplished with either an operator interface display or an industrial computer, she observes. And those users heading in the computer direction tend to be very interested in collecting data, Tur adds.
Easy configuration
The push for easier configuration tools for both HMIs and industrial computers will continue, adds Blake Moret, business manager of the information-platforms unit at Rockwell Automation (www.rockwellautomation.com), Milwaukee. He believes that the easier it is to use multiple software applications—and the better these applications play together—the less of a problem to use those applications with ICs.
Another trend, observes Tur, is more users wanting Internet access, especially among machine builders, packaging original equipment manufacturers and water/wastewater plant operators. And they want that access, plus data collection capabilities, more cost-
effectively in an operator interface, she says. “I’ve noticed interest in operator interface displays that have extra memory capabilities through a flash card or USB (universal serial bus) port,” Tur adds.
Tur notes two other developments. One is an “HMI-in-a-box”—essentially a small Web server in a box the size of a small PLC with an Ethernet port accessible by a computer running a Web browser. The other is using the industrial computer in the network as a gateway between the machine network and business systems.
不管趋势,运营商接口不会gain at the expense of ICs, or vice versa, says Moret. “Rather, it’s a need to strengthen capabilities from the low-end HMI dedicated terminals—with more flexibility—up through the high-end industrial computers having industry standards and operating systems that give virtually limitless combinations of software that can run on the industrial computer platforms.”
One final developing trend in operator interface involves the distribution model. Cummins, Ga.-based AutomationDirect (www.automationdirect.com) pioneered a direct-ship model for automation components almost ten years ago. It later included operator interface devices. The model must have traction, as AVG Corp. (www.avg.net), based in Bettendorf, Iowa, has recently also begun selling operator interface via the Web.
C. Kenna Amos,ckamosjr@earthlink.net, is an Automation World contributing editor.
