It used to be that you'd buy an human-machine interface (HMI) just to get an operator interface (OI); that is, a device that lets you look into the machine to see what was going on, and adjust or control what you saw. Plain-vanilla OIs are certainly still available, but the overall role of HMIs is changing. Today, HMIs are taking over control, data acquisition, web access, maintenance, diagnostics and enterprise functions. The OI function remains, of course, but telling an operator what is going on seems to be the least of an HMI's many tasks.
Virtually all desktop and panel HMIs now are based on a PC architecture and run some version of Windows. A certain number of handheld and PDA-based HMIs also are appearing and, while all are not Windows-based, the ones we see are compatible with the Windows architecture.
The “big iron” HMIs can be extremely powerful PCs, capable of running just about any control, data acquisition or SCADA software package. Many HMIs serve as the gateway between a machine and its CMMS, ERP, supply chain, and other high-level software packages. That is, they gather the data from plant floor equipment, put it into XML or some other common database format, and ship it off to the enterprise software in a timely fashion.
HMIs also can be extremely tiny, embedded, diskless processors that operate inside equipment and machines. When equipped with an embedded Windows operating system such as Windows CE, the embedded systems provide many of the functions of the big iron systems.
HMIs big and small also serve as the gateway to the web for many machines. The HMI hosts the necessary web servers that allow remote PCs or HMIs to access web pages via the Internet. Web access lets your customer be paged at home, receive an e-mail that tells him of a problem at the factory, helps him find out what is going on via his home PC's browser, and allows him to make the necessary setpoint changes at 3:00 a.m.—all without having to run back to the factory.
For a machine builder, embedding an HMI with web capability helps with after-sales support. With a built-in web server, control software updates, bug fixes, diagnostics and other functions can be accomplished remotely. For example, if a customer reports a problem, web-based diagnostics may be able to identify and solve the problem without sending a technician.
The new breed of HMI/SCADA systems are selling fast. ARC Research says the HMI software market will reach $559 million by 2008, an annual growth rate of 5%. That's faster than the overall automation market. “HMI and related software has become a critical component in the infrastructure for successfully managing manufacturing operations,” says ARC's research director, Craig Resnick.
Industrial flat-screen monitors are available with 15, 17 and 21-in. displays, with or without touchscreens. The monitors carry a NEMA-4 rating, and touchscreen models use analog-resistive technology. Mounting of the monitors has been simplified with the use of an easy-clip mounting system. Automation Systems Interconnect; 877/650-5160; www.asi-ez.com
Touchscreen Computers Run HMI Software
Operator Interface Computers are fully functioning, touchscreen computers with a Windows XP Professional operating system. They contain an embedded XP option using Compact Flash technology for harsh environments. A quick-change mechanism enables easy maintenance by allowing a quick connect or disconnect of the display from the computer. Options include 10 and 12-in. display screens plus connectivity support for PLCs, drives and other industrial devices. Wonderware 949/753-9292x244; www.wonderware.com
The ControlNet Scheduled Communications module provides deterministic, repeatable communication for PanelView Plus HMI and VersaView CE computers. Unlike unscheduled communications, which use leftover bandwidth as it becomes available, the scheduled module takes priority placement on the network's bandwidth, guaranteeing that a signal will transmit within a specified time period. Users can schedule how often a controller is updated with data. Rockwell Automation; 800/223-5354x1769; www.ra.rockwell.com
HMI Software Is a Snap
IODisplay helps machine builders develop operator interfaces that communicate with the company's Snap-LCE controllers and Snap Ultimate I/O controllers. The HMI has alarming, trending, security, and a built-in library of 3,000 industrial automation graphics. It also has a multithreaded scanning engine. Opto 22; 800/321-6786; www.opto22.com
Display Uses Flash to Swap Apps
The 5.7-in. HG2F display has a built-in Compact Flash slot that will accept standard CF cards up to 512 MB. A CF card can store multiple projects that can be transferred to another operator interface without using a computer. In addition, alarm and trend log data, recipe data and hardcopies of the screens can be saved to a CF card. IDEC; 408/745-5257; www.idec.com
Where in the World is …?
InstantHMI PDA Clipboard validates data entries by automatically recording the person's physical location and time when data is entered. Using the Global Positioning System, the location of the device is always known. Bar coding and RFID can be used to make the capturing of data automatic and more reliable. The HMI is compatible with Allen-Bradley, Koyo, Mitsubishi, Modicon, Omni Flow, Siemens, Trio, Toshiba, Watlow, Wago and Yaskawa controllers. Software Horizons; 800/664-2000; www.InstantHMI.com