PCs Lead the Way in Operator Display

The past decade has seen enormous changes in human-machine interfaces (HMIs). At the low end, electronic operator interfaces (OIs) have successfully replaced many hard-wired panels as the interface of choice. Priced under $2,000, with some as low as $500, electronic OIs provide more functions at lower costs than hard-wired controls.

By Jane S. Gerold, Control Engineering June 1, 1998


Human machine interface

Industrial computers

Flat-panel displays

Microsoft Windows

Operator interface

Sidebars: White box vs. industrial computer—how tough is enough?

The past decade has seen enormous changes in human-machine interfaces (HMIs). At the low end, electronic operator interfaces (OIs) have successfully replaced many hard-wired panels as the interface of choice. Priced under $2,000, with some as low as $500, electronic OIs provide more functions at lower costs than hard-wired controls.

At the high end, industrial personal computers have become front-ends to supervisory control, data acquisition, and programmable logic controller (PLC) systems. These same industrial workstations are also doing duty in PC-based soft logic systems, providing both the control engine and display.

To meet these new demands, industrial workstations incorporate larger flat-panel displays, faster processors, and options for networking, multimedia, and bundled software. Fortunately for users, the improved capabilities leverage commercial PC developments, which keeps costs low and performance high.

Built tough

Since the mid-1980s, when PCs first appeared on the factory floor, the debate has raged over whether “white box” PCs are suitable for industrial use. A recent study by Venture Development Corp. (Natick, Mass.) reports that office-grade PCs are being used in light industrial applications, while their rugged cousins are applied in harsh environments. (See in this article, “White Box vs. Industrial Computer.”)

With PCs playing more critical roles in automation applications, factors such as uptime, reliability, and power integrity are as important to consider as the environment. An office-grade PC may survive in a light-industrial atmosphere, but it may not survive 24-hour-a-day, 7-day-a-week use.

To serve critical applications, Rockwell Automation/Allen-Bradley (Milwaukee, Wisc.) has introduced RAID (redundant array of inexpensive disks) technology in its line of RAC6000 industrial workstations. Says Jim Renehan, open platform products marketing manager, “Any application that is mission-critical, disk intensive at runtime, or uses virtual memory to shuffle programs in and out of memory faces an immediate threat of disk failure and is a good candidate for RAID. Users will see immediate benefits in increased reliability and system integrity.”

Power supplies pose additional threats, with a power glitch capable of crashing the computer. Allen-Bradley uses UPSs (uninterruptable power supplies) in conjunction with Windows NT so its industrial computers do a “soft landing” in the event of a power outage.

Vibration and shock mounting, heat dissipation, and EMI/RFI immunity are other factors to consider in an industrial PC. Azonix Corp. (Billerica, Mass.) cites the rule of thumb that, for every 10 °C rise above normal operating range, system life is cut in half. As well, new demands from bigger screens, more powerful processors, bigger disks, etc., will actually increase failures due to shock, vibration, and temperature rise.

Azonix has designed its ProPanel low-power computer with shock mounting, electrical isolation, internal fan, and passive convection cooling—claiming a seven-year life in a 0-30 °C environment. The company was one of the first to apply flat-panel displays in its systems and since has introduced sealed units and a purging system for hazardous environments called SmartPurge. New for its flat-panel displays is a “hi-brite” option that self-adjusts screen brightness according to ambient light conditions. ProPanel has enjoyed two recent design wins. It was selected as Fisher-Rosemount’s (Austin, Tex.) OEM industrial workstation and by Baker-Hughes for use in off-shore oil exploration.

If your application runs 24-hours-a-day, another factor to consider is how to repair or upgrade computer components under power. New from AVG-Uticor (Carol Stream, Ill.) is the Arjun Series with hot-swappable display. Available with 10-, 12-, and 14-in. flat-panel touchscreen displays, the Arjun has a two-piece design that allows the monitor to be mounted several feet away from the processor.

Size matters

Overall footprint is another important factor in system selection. When the application space is smaller than a breadbox, or when it can benefit from a 20-in. display, size matters.

On the small end, measuring 10-in. by 9-in. by 4-in., is the new 9400 Series from Xycom, Inc. (Saline, Mich.). With 133 MHz processor, 64 MB DRAM, 1.3 GB hard drive, on-board PCI, and two PC-104 sites, the 9400 can be configured to run open PC application software. Prices for the color touchscreen display versions start under $3,000. A node box version (no display) starts under $2,000. All units carry the CE Mark and are certified for Class I, Div. 2 hazardous use.

At the other end of the size spectrum is the new WS4006 from Rockwell Automation/Intecolor (Duluth, Ga.), a NEMA 4/4X/12 workstation with integrated 20-in. industrial CRT. The completely sealed computer accepts CD-ROMs, tape backups, and DVD without need for additional enclosures.

Intecolor also offers a full line of industrial display monitors, including CRTs and flat-panel displays. Its newest flat-panel monitor is a 20-in. active matrix TFT display with 160° viewing of 1,280 by 1,024 color resolution. The monitor has touchscreen options, is CE certified, and panel-rated for NEMA 4/12.

Calling it WOW (wide-on-wide) viewing technology, Aydin Displays (Horsham, Pa.) announces its 20-in. active matrix LCD flat-panel display. A 160° viewing angle, horizontally and vertically, and 1,280 by 1,024 resolution are said to “bridge the gap between LCD technology and CRT functionality.” A variety of packaging options are offered including: plastic and metal desktop; industrial console, rack, and panel mount; and ruggedized military and harsh environment.

A start-up company, Viewtronix Inc. of Saline, Mich., has also gotten into the 20-in. flat-panel business with its SXT2010 NEMA 4/12 monitor. The Viewtronix family includes screen sizes of 10-, 12-, 14-, 15-, and 20-in. monitors with resolutions ranging from VGA through SXGA. The 20-in. model requires less than five inches of cabinet depth, includes front-panel controls, and is priced at $11,995 with $550 touchscreen option.

As flat as that

Peter Kaszycki, president of Pro-Tech (Suwanee, Ga.) lists some benefits of flat-panel displays over CRTs.

Smaller size, weight, depth;

Lower power consumption;

Reduced heat generation;

Brighter, crisper displays.

To leverage these benefits, Pro-Tech introduces its new Profile Series, an industrial flat-panel workstation system that interfaces to any PC, including popular desktop models, with remote display up to 600 ft. from the PC. Active-matrix displays, which are offered in sizes from 13-in. to 18-in., are mounted in sealed, washdown, flex-arm enclosures that can tilt and rotate. Options include touchscreens, industrial keyboard and mouse, and fixed or mobile pedestals.

At 3.5-in. deep for a 15-in. display, the new Vamp-SmartSize from Computer Dynamics (Greenville, S.C.) is a flat-panel CRT replacement with optional touchscreens. It’s said to solve the dual problems of displaying low-resolution on a high-res screen and handling interlaced full motion video and scanned computer graphics. Problems can result when the resolution and interlacing of the video source differs from that of the LCD, such as may occur in the replacement of a CRT with a set-resolution digital LCD.

Computer Dynamics uses a scaling circuit that resizes a 640 by 480 resolution image to fill an 800 by 600 or 1,024 by 768 LCD. A spatial de-interlacing circuit solves the interlaced video problem (large LCDs are non-interlaced) by converting each field to a full frame for a near-perfect image that maintains the source signal’s original refresh rate.

Pentium power is at the heart of a new workstation from Siemens Energy & Automation (Alpharetta, Ga.). The Simatic PC F125 features a 10-in. flat-panel color display with optional touchscreen. A unique feature is the optional SafeCard monitoring module. This built-in display on the front panel alerts the operator to any system problems, such as unsafe operating temperature or program lock-up.

Combining hardware and software

Bundling the PC workstation hardware with software can offer several advantages to the user in installation and setup. To reduce the risk of incompatible drivers, operating system software, and I/O interface cards, some users may prefer to purchase a complete HMI system.

Total Control Products (Melrose Park, Ill.) offers several systems that bundle hardware and software from its various operating divisions, including Taylor Industrial Software (Edmonton, Alberta, Canada) and Computer Dynamics. Total Control’s Op Center is an industrial PC that can be ordered loaded with Windows NT, operator interface software (Taylor’s fxView), control software (Taylor’s fxControl), and an I/O interface card. Says product marketing manager Gimmi Filice, “With Op Center, there’s no driver setup, no application installation, and no operating system installation. The user creates the application and runs.”

Looking to the future, Mr. Filice comments on the increased acceptance of PC-based control. “In most cases, the PC running the control software will also be running the HMI, requiring higher performance hardware. This is where it will be increasingly important that the HMI and control software work well together on the same PC.”

Also bundling hardware and software are GE Fanuc’s (Charlottesville, Va.) Display Stations with Cimplicity HMI. Says program manager Susan Meador, “Our customers receive a fully tested, integrated product at a great pricing deal on the bundled package. They have the additional advantage of a single source of technical support for hardware and software.”

GE Fanuc’s Display Stations offer Pentium processors, 10-in. and 14-in. active matrix flat-panel display screens, touchscreens, integrated keypads, ISA and PCI expansion slots.

While bundling hardware and software makes sense for some users, others prefer the wider choices available with separate purchases. For these users, the new multimedia industrial PC workstation from American Advantech Corp. (Sunnyvale, Ca.) allows loading of any CD-based software on the integrated CD-ROM.

Advantech’s AWS-842TP offers a 10-in. TFT LCD display, ISA/PCI passive backplane, NEMA 4 or IP65 front panel, and two sealed membrane keypads. The CD-ROM is accessible through a front-panel door. Prices start at $3,290.

Value-added support

Hardware improvements, such as adding CD-ROMs, faster processors, and larger flat-panel displays, enhance industrial workstation performance, but there is a price to pay. The commercial market that drives more function for less cost also dictates a built-in obsolescence. Today’s computer components may not be available 12 months from now. For someone designing an automation system, this short product life can make PC-based control a risky proposition. Users must ensure product availability and support from vendors.

One solution comes from Contec Microelectronics, (San Jose, Calif.), with its Special Long Supply program. Contec emphasizes longevity, product design, and long-term hardware support. For example, its Box PC has guaranteed hardware support until the year 2006.

In addition to long-term support, users want vendors to customize solutions in a minimum amount of time. Rittal Corp. (Springfield, O.) recently announced a “build-to-order” service program for quick turn-around on customized workstation units.

Rittal’s VIP 6000 operator interface line has been expanded to include a wider variety of flat-panel displays and accessories. With the customization program, users can have a specialized VIP sized and built to order in about 10 days.

The “flexibility to adapt” is a key benefit of Automated Control Concepts’ (ACC, Neptune, N.J.) product line, according to industrial workstation consultant Deborah Heidelbaugh. Similar to other vendors, ACC counts its value-added services in four main areas:

Sales—application assistance and configuration;

Production—factory mounting, wiring, and acceptance testing;

Documentation—NT configuration, serial number, and wiring details; and,

Support—warranties and tech hot-lines.

A view on the future

With industrial workstations marching to the same beat as the commercial market, expect to see developments that leverage the Internet, Ethernet, and component object technology. Already, industrial vendors are launching ruggedized Web browsers, integrated network functions, and Microsoft Windows CE stations.

One of the first to introduce a Web machine is Ann Arbor Technologies (Ann Arbor, Mich.) with its WebLink workstation. Says vp Dan Benson, “With the capability to develop industrial software screens in HTML, an in-dustrial Web browser can dramatically reduce the price of an HMI.”

A challenge faced by industrial vendors is selecting which commercial developments to implement in their products. Mark Smith, director of marketing at CTC-Parker (Computer Technology Corp., Milford, O.) comments, “We are constantly evaluating the general PC market to identify which features would benefit factory-floor HMI workstations.” CTC has incorporated built-in Ethernet and compact FLASH in its PowerStations. Continues Mr. Smith, “Ethernet provides our customers with a high-speed interface, while FLASH eliminates the reliability issues of a hard drive.”

Ted Schneider, product manager at Cutler-Hammer (Columbus, O.), says his company takes many features from the PC industry and combines them with industrial features to create automation PCs for the control customer. “Internet connectivity is Cutler-Hammer’s latest frontier. Our NetpoiNT software provides HMI function with Internet connection.” NetpoiNT is one of the packages that can run on Cutler-Hammer’s D700 computers. The series was recently expanded to include 15-in. active matrix displays with touchscreens.

The first diskless industrial computer running on Windows CE was announced in March by Dynapro (New Westminster, British Columbia, Canada). The ET4500 is part of Dynapro’s strategy for a scaleable, portable workstation architecture. Workstations running Windows NT HMI and SCADA software power the upper end of the performance curve, with Windows CE stations at the lower end.

Dynapro cites several features of Windows CE which suit its low-end workstation role:

Windows CE is optimized for diskless operation, providing higher reliability;

Windows CE machines will be less expensive than other industrial PCs;

Windows CE offers low memory footprint, built-in PCMCIA support, and standardized hardware driver support; and,

Perhaps most important, Windows CE leverages Microsoft Windows’ common look-and-feel, development tools, and cross-platform application.

What comes next? According to Peter Zornio, director of systems research for Honeywell IAC (Phoenix, Ariz.), “Lower cost and maintenance Network Computers, with features such as Microsoft’s Zero Administration Windows, will penetrate the industrial HMI market. The ability to preload HMIs with only the needed functionality and have a minimum of administration is extremely beneficial.”

Mr. Zornio also predicts a bright future for component object technology in HMIs. “Future industrial displays will consist of specific HMI application components as ActiveX controls, Java applets, and dynamic HTML objects that are executing in commercial off-the-shelf containers such as web browsers.”

Stay tuned for the next quantum leap in industrial workstations. Rest assured that, wherever commercial software may lead them, industrial hardware vendors will be close behind with products to fill the need.

White box vs. industrial computer—how tough is enough?

Do you use an “off-the-shelf” commercial personal computer (white box) for your industrial PC-based applications? Do you insist on rugged computers made specifically for the industrial environment? Venture Development Corp. studied the current issues of white box versus industrial computers.

The study included procurement levels of industrial and office grade (white box) PCs and WSs (work stations) for industrial applications along with likely future trends both in general and by specific use. The study also examined the important factors used for choosing the type of computer and what improvements users wanted.

According to the survey, 63.5% of the units currently purchased are industrial grade computers. That is predicted to increase to 69.3% by 2001.

Environment classes

Varying application environments exist within an industrial setting. The study defined three as harsh office, light industrial, and heavy industrial. Environment severity increases as applications shift from harsh office to light industrial to heavy industrial. Typical of these more demanding requirements are wider temperature ranges, more relative humidity, more shock & vibration exposure, and greater need for airborne particulate and liquid splash/cleaning protection.

Not surprising, office (white box) units are predominantly used in harsh office environments, and industrial grade units in heavy industrial. Harsh office purchases are expected to shift marginally to industrial grade units, and a comparatively larger percentage of industrial grade units are expected to be purchased for light and heavy industrial applications.

Decision criteria

For harsh office applications, price was the predominant consideration for deciding on which product to purchase, and considerations of ruggedness and environment were mentioned by less than 10% of the users.

For light industrial applications, price was still the most mentioned consideration, but by a smaller percentage of users, and reliability was considered more important. Users still considered price for heavy industrial applications, but ruggedness/robustness and reliability were considered much more important. (See table for summary of results.)

Larger display size, overall smaller computer size, and higher speed were the most desired improvements for industrial PCs. For white boxes, users ranked desired improvements as larger displays, higher speed, and increased reliability in their white boxes.

Study Source: “The Worldwide Market for Ruggedized/Industrial Personal Computers and Workstations, Third Edition;” Venture Development Corp., One Apple Hill, Natick, MA 01760; 508/653-9000; Fax: 508/653-9836; E-mail: sales@vdc-corp.com ; Author: Dinender Sharma, research analyst.

White Box or Ruggedized: Which Factors Are Most Important?

Percent of respondents

Source: VDC, Natick, Mass.All othersUnder 9% each

Harsh office




Dirty environment

All others
Under 5% each

Light industrial



Temperature range


All others
Under 5% each

Heavy industrial




Vibration resistant