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PCs tackle industrial applications.

PCs Tackle Industrial Applications

On the factory floor, the personal computer has come a long way in a short period of time. Equipped with high-performance microprocessors and packaged into rugged enclosures, today's PCs have the power to tackle industrial applications and the toughness to withstand harsh factory environments. At the same time, powerful software specifically designed for industrial applications is appearing.

As a result, the industrial PC is assuming a broadening role. The PC serves as a tool for data acquisition, a controller of other instruments, and an interface to programmable logic controllers. The PC can itself function as an instrument, performing high-resolution readings of flow, temperature, pressure, level, or other phenomena at resolutions of a microvolt or less. It can perform sophisticated on-line data analysis, and can port data to other applications programs for spreadsheet analysis, graphing, and mathematical manipulation. It can also readily act as an interface between remote factory locations and control rooms, mainframe computers, and other PCs. Often, it is configured together with a large number of systems in a distributed-control environment.

In terms of both applications and manufacturers, variety has come to the industrial PC arena. New offerings include microcomputer boards that plug into PCs and turn them into powerful industrial systems, small portables that can be moved around the factory, and larger units that rival workstations in power. OEM-manufacturers are outfitting the Macintosh for the factory. Software companies are developing improved operator-interface, graphics, and process control packages.

Decentralized Control

Microcomputer boards, also known as board-level products, are one manifestation of the trend towards decentralized control in the factory. Some boards are intended to function as stand-alone computers. Others are built to be installed in PCs by plugging them into expansion slots. As PCs are typically equipped with several slots, this allows each PC within a factory to be customized to perform different embedded control, data acquisition, and monitoring functions. Typically, such setups can be put together at a fraction of the cost of equivalent mainframe or minicomputer systems.

The MLC-XT board from Micro Linear Controls (Racine, Wis.) is billed by its manufacturer as the PC XT of the industrial world. It consists of a half-height XT Bus card that acts as a base where memory chips and the Intel Wildcard-88 computer board plug in. A slot is also available for up to 2 MB of solid-state disk memory; optional EPROM memory is also available. The MLC-XT also has a watchdog timer for control applications; if the computer fails, external pumps, valves, or motors can be automatically returned to their default states. There's also a power monitor to prevent unpredictable behavior by holding the computer at the reset level until power stabilizes.

The Intel Wildcard concept, introduced last year, employs chip-on-board technology to achieve the ultimate in board miniaturization. The Wildcard-88, for example, is just 2 x 4 in. It represents a 75 percent reduction in parts count over the PC XT, yet it contains the 80C88 CMOS microprocessor, a peripheral chip for memory management, interrupt control, timer/counter functions, a socket for Netbios software, and another socket for the 8087 coprocessor.

For high-speed, high-accuracy data acquisition and control applications, National Instruments (Austin, Tex.) makes the Lab-PC. The board, which can be used with PC XT, AT, and PS/2 systems, features eight single-ended analog input channels, two 12-bit double-buffered analog output channels, 24 digital I/O lines, three counter/timers for timing I/O, and direct memory access.

The SBC-200B dedicated board-level microcomputer from Industrial Computer Controls (Paoli, Pa.) is packaged in a NEMA 12 enclosure and has a 2-MHz microprocessor. In place of a PC monitor, it uses a two-line 20-character alphanumeric vacuum-fluorescent display and in place of the keyboard, it has a 5 x 5 array keypad with numeric and special functions. Software is put into EPROM (instead of on a floppy disk). Because of this arrangement, such single-board microcomputers are typically more rugged than a PC.

At the opposite end of the spectrum are systems that accept expansion boards. The ICS-4000 Controlstation from Nematron Corp. (Ann Arbor, Mich.) has six open expansion slots on a passive backplane that can accept boards for I/O and network interface, scanners, and IBM's Artic coprocessors, allowing the Controlstation to function as a cell controller. It is available with either the 16-bit 80826 or the 32-bit 80386 microprocessor and with up to 16 MB of hard-disk memory rated to operate at up to 50 [degrees] C. A battery-backed 6-MB solid-state disk is also available.

Additional slots are available in the model 556 measurement and control system from Keithley Instruments (Cleveland, Ohio). This external mainframe accepts up to 10 plug-in data-acquisition cards for the IEEE-488 bus. When configured with Keithley's AMM2 analog/digital converter card, the 556 is capable of 6000 16-bit samples/second data acquisition over the bus.

Portability Is In

Portability can be an asset in operations such as setting up temporary applications around the factory or performing off-site data entry. In this category, perhaps the smallest unit available is the Agilis, a hand-held 8.85 x 11 x 2-in. PC that weighs less than 10 lb. Made by Agilis Corp. (Mountain View, Calif.), it consists of networking and computing modules that house 80386 and 8088 microprocessors. Other modules are for battery backup, a floppy disk drive, and radio communication. Each modules over an Ethernet backplane. and communicates with the other modules over an Ethernet backplane. All the electronics are housed in a NEMA 4 case. The Agilis also has an optional touch screen feature. Communication is performed using spread spectrum techniques over a 100-m indoor (1000-m outdoor) range, at 230K per second.

Another portable industrial PC is the Baby Blue III from Transduction Ltd. (Mississauga, Ontario, Canada), which measures 11.5 x 6.5 x 3.25 in. It features an NEC V40 8-MHz microprocessor and floppy disk and communications ports and it operates from 5 volts and holds up to 1 MB of memory.

In portables as well as larger industrial systems, battery backup is a feature that's becoming more common. Action Instruments (San Diego, Calif.) provides up to 15 minutes of battery backup operation from its BC-04 Matchbox PC that consumes less than 25 watts of power. Available in PC AT- and XT-compatible versions, it features three expansion slots and a watchdog timer. It earns its name with a size of just 10 x 4 x 6.4 in.

Somewhat heftier than true portables are industrial PCs in the 20-lb range. These units have been dubbed transportables. The model 6008 from Texas Microsystems (Houston, Tex.) is encased in a heavy-gauge-aluminum enclosure that has briefcase-like handles. It has a 10-slot backplane and integral hold-downs for PC XT and AT boards. A full-size keyboard and a 12-in. liquid-crystal flat-panel display add up to a PC that measures 15.5 x 14.5 x 6 in. and operates from a 10- to 20-volt dc battery at 160 watts. There is a tradeoff, however; due to the extra rugged packaging the unit weighs some 23 lb.

Many industrial PCs pack so much power that their performance borders on that of larger workstations. An example is the model 4190 from Xycom Inc. (Saline, Mich.). Compatible with the PC AT, it has a 25-MHz 80836 microprocessor and a VGA color monitor and it can handle all popular process control and automation software packages like Genesis, the Fix, and On-Spec. It also works with all available PLC software packages, Digital Equipment's DECwindows via plug-in Ethernet controllers, and DECwindows Display Facility software. A passive backplane contains 12 slots and can accept a coprocessor. Processor and bus speeds can be set independently for 6, 8, 10, 12, 16, or 25 MHz. Also included is a watchdog timer, power fail/restart capability, 1 to 4 MB of memory, two RS-232C ports, parallel ports, controllers for the VGA monitor, and a 20-MB 3.5-in. drive. The industrially hardened 19-in. VGA monitor has a resolution of 640 x 480 pixels and a 260,000-color palette. The screen is protected by a Lexan shield that's sealed to NEMA 4 and NEMA 12 standards. The 4190 operates at up to 50 [degrees] C and can handle from 10 to 80 percent humidity noncondensing and vibration of 1.0 g maximum from 5 to 200 Hz of 0.006-in. peak-acceleration shock at 11-millisecond durations can also be handled.

Motorola Computer X (Schaumburg, Ill.) also makes industrial computing platforms that resemble workstations but at a lower cost. Their cX platforms are designed for real-time distributed computing and have distributed architectures for 3-, 10-, 12-, and 20-slot VMEbus boards. They feature 16- and 25-MHz 32-bit 68030 microprocessors, complementary 68882 floating-point coprocessors that deliver from 3 million to 5 million instructions per second of performance, and either 4 or 8 MB of memory. Also available are SCSI peripheral controllers, 720K of 3.5-in. disk memory, 48K or 104K of hard disk memory, 150 MB of streaming-tape memory, and Ethernet capability. Prices range from $7800 for a 4-MB 16-MHz diskless model cX034 to $15,500 for an 8-MB 25-MHz cX030 computer with 150 MB of streaming-tape memory and 104 MB of hard disk memory.

A single virtual machine architecture characterizes the cX family. The architecture creates a seamless distributed system that makes knowledge of the physical location of resources, processes, or nodes irrelevant to the user runig an application. And applications can be expanded in a modular manner as needs grow, by using add-on boards from over 250 VMEbus board manufacturers. The family uses the CoRes dual operating system, a full Unix System V Release 3 development environment, and third-party application software.

Earlier this year, IBM took the wraps off industrial versions of its PS/2 family. All the systems are based on the 32-bit Micro Channel Architecture (MCA). MCA has been part of IBM's factory floor products since 1980. At that year's Instrument Society of America convention, IBM introduced the MCA in the model 7552 Gearbox, a PC that resembles a PLC. The Gearbox uses a 10-MHz 80286 microprocessor.

The industrial PS/2 family includes an entry-level bench-top rack-mountable model 7541/7542. The system runs on MS-DOS and the OS/2 operating system using a 80826 microprocessor. It has three 16-bit MCA slots and holds up to 2 MB of memory.

A notch higher in performance is the bench-top rack-mountable model 7561/7562. It uses the 20-MHz 80386 microprocessor and features two 16-bit and two 32-bit MCA slots. It holds up to 8 MB of memory. All models feature extended shock and vibration protection, 150-watt self-ranging power supplies that operate from 110- and 220-V ac lines, and filtered cooling for high-temperature operation.

In industrial applications, the systems are sometimes used remotely from their keyboard and monitor. For applications such as quality control, the computer, keyboard, and monitor may be located together. For harsher environments such as process control, the computer is located in a safe place and the hardened keyboard and monitor are located remotely on the plant floor, connected to the PS/2.

In the industrial environment, PLCs also find themselves distributed about the factory. The PLC, which preceded the PC into the factory, is a hardened industrial computer that is somewhat limited in function. It performs basic relay switching and contact-sensing functions. PCs are now often used to program PLCs. A machine specifically designed to function as a PLC programmer is the Workmaster II portable programming unit from GE Fanuc Automation (Charlottesville, Va.). This factory-hardened unit uses an 80386 microprocessor and is fully compatible with the IBM PS/2 family. It can be used to program GE Fanuc's new Series 90, Series Five, and Series Six PLCs. Weighing 20.8 lb and measuring 18.3 x 1.9 x 5 in., it holds up to 2 MB of main memory, 1.44 MB of 3.5-in. diskette memory, and 30 or 60 MB of hard disk memory.

A Role for the Macintosh

Apple Computer, for its part, is targeting the industrial PC market with its Macintosh PC. Apple, in fact, has been using the Macintosh in its Fremont, Calif., facility since 1982, as an integral part of the firm's Apple Flexible Manufacturing System, a computer-integrated manufacturing strategy under which Macintosh PCs are manufactured.

Manufacturers of automation equipment like Automatix (Billerica, Mass.) have taken the Mac II with its excellent graphics capability, hardened it for industrial applications, written software around it, and produced powerful industrial PCs. Automatix, in fact, was the first to introduce 32-bit PCs on the factory floor, before IBM made its inroads.

Automatix's FactoryMac is the first industrially packaged Mac II computer. Featuring the 32-bit NuBus, it can act as a cell controller, an intelligent shop-floor terminal, a test-stand controller, a data-acquisition and analysis system, an instrument controller, and a production monitor. The PC includes a 16-MHz 68020 microprocessor, a 68881 floating-point math coprocessor, and 1 MB of RAM memory expandable up to 888 MB. Additional memory expansion via the NuBus slots provide a maximum of 2 Gbytes of memory address space.

To make the FactoryMac even more compatible with the factory floor environment, Automatix installed a larger speaker than the one normally used. This makes the machine useful for verbal annunciation of alarms and for communicating such things as diagnostics and possible machine maintenance instructions. There's also no need for an operator to boot up the operating system; this is done automatically when the power is turned off. For its operating system, the FactoryMac can run Apple's Unix-like A/UX software. MS-DOS can be run with the use of the Mac286 plug-in board from AST Research (Irvine, Calif.).

The FactoryMac is available in 19-in. rack-mountable, panel, or desktop versions, housed in a NEMA 2 drop-proof enclosure with filtered ventillation and radio frequency interference shielding for noise immunity. It has a 5 to 95 percent noncondensing relative humidity rating and can operate over a temperature range of 10 [degrees] to 50 [degrees] C.

In terms of applications software, Automatix has just made available Image Analyst 7.1, an industrial image-analysis package. Featuring a multilevel user interface, it is aimed a both the novice and the experienced user. For those who don't want to write their own programs, it allows sophisticated image processing and measurement routines. It can be modified by those unfamiliar with image processing programming by using Image Analyst/Source. It can also be programmed in C, with a complete image-processing subroutine library available from Automatix.

At Motorola's Boynton Beach, Fla., facility, where paging systems are manufactured, an Automatix Mac II-based system was chosen as as cell controller for robotic and machine vision operations. Using the Mac II, engineers at Motorola's Robotics Development Group came up with the GRACIOUS (Graphical Robotic Automation Controller Including Ordinary User Simplification) system, which provides a simplified user interface to control a variety of complex tasks.

Software: A Key Factor

The most important reason for the PC's invasion of the factory floor continues to be the availability of good software packages. Hundreds of MS-DOS software packages are available for IBM PCs and compatibles, and there are packages for the Macintosh PC as well. Users can now buy boards to run such software on the STD Bus, the VMEbus, the Multibus I and II, and the NuBus.

There is now fault-tolerant software for the IBM PC for real-time process monitoring and control applications. Available from Laboratory Technologies Corp. (Wilmington, Mass.), Labtech Control-FT provides users with a complete set of industrial control functions, including process monitoring and control, real-time operator interfacing, on-line statistical process control analysis, open-architecture networking, and fault tolerance and redundancy.

Improvements are also being made in operator-interface software. For example, Wonderware Software Development Corp. (Irvine, Calif.) recently announced InTouch, a software package for use in creating and running control-system operator interfaces on IBM PCs and compatibles. Designed specifically for use by design engineers to aid in the automation of process or machine control applications, it consists of two major elements: WindowMaker for developing the application and WindowViewer for running it.

WindowMaker is used to create the animated graphic display windows and the tag name dictionary that comprise the operator interface. Using the keyboard and a mouse, an engineer can use WindowMaker's editing capabilities to create an interface for one or more controllers. WindowViewer is a run-time environment that process operators can use to display and animate the graphic windows created with WindowMaker. It provides plant operators with a dynamic graphic representation of the entire process or plant being controlled, so that they can interact with the control system using a keyboard, a touch screen, or other pointing device. Both packages run on any IBM PC or compatible with at least 640K of memory and can run Microsoft Windows 386 Version 2.11 or higher. For optimum performance, an AT-class PC with at least 2 MB of memory is recommended.

Many software packages are available for instrument control, data acquisition, and analysis. One popular package is LabWindows from National Instruments. The firm recently upgraded LabWindows to version 1.2 for IBM XT, AT, and PS/2 PCs. The upgraded software features a fully integrated driver for National Instruments' Lab-PC plug-in data-acquisition board.

Some Limitations

Though the majority of industrial PCs use MS-DOS as their operating system, according to many experts MS-DOS has a limited lifetime for industrial applications and will go the way of CP/M. For one thing, it has a 640K limit, too little for many industrial tasks. For another, it can only be used in a single task, and many industrial applications are multitasking. Although some multitasking has been tried with MS-DOS, no such standard exists. And MS-DOS does not match the power of newer hardware such as the powerful 80386 microprocessors. Furthermore, available application software is outstripping the capabilities of MS-DOS.

These experts foresee MS-DOS being replaced with OS/2, Unix, and the Macintosh O/S operating systems. The first two are multitasking; the last one is expected to become so.

PHOTO : Apple for industry. Automatix has packaged the Macintosh II in a NEMA 2 industrial enclosure and added powerful applications software to create the FactoryMac, the first industrial version of the Apple machine.

PHOTO : Powerful platforms. Designed to perform like workstations but at a lower cost, the cX systems from Motorola Computer X are built for real-time distributed computing. They can execute from 3 million to 5 million instructions per second.
COPYRIGHT 1989 American Society of Mechanical Engineers
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Copyright 1989 Gale, Cengage Learning. All rights reserved.

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Author:Horn, David
Publication:Mechanical Engineering-CIME
Date:Dec 1, 1989
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