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Great graphics, unlimited flexibility for new controls & CIM family.

Great Graphics, Unlimited Flexibility For New Controls & CIM Family

Stunningly realistic graphics on a touchscreen that can emulate sliding limit switches, thumbwheels, dials, toggle switches, and pushbuttons--totally eliminating the need to read text or tap a keyboard--are just one of many intriguing new features of a modular, "ruggedized" family of controllers and monitors to be introduced at NPE '91 in Chicago this June. Buhl Automatic Inc., Guelph, Ontario, is introducing its IQ Series of hardware and software components as building blocks for plant-wide computer-integrated manufacturing (CIM) systems in injection molding, extrusion and blow molding. First shipments will begin in September.

Buhl's executive v.p. and general manager Gary Bartholomew sees these new hardware "platforms" as key elements in its plans to realize the concept of the "intelligent factory." Realizing that concept will require development of a number of new software packages employing "artificial intelligence" techniques, beginning next year.

But the key first step, he says, was to create the right modular elements. Essential requirements were that they be durable, easy to use, offer the flexibility to match cost and capabilities to a variety of users' needs within a single family of compatible elements, be expandable cost-effectively, and be an "open system" based on industry standards, so as to be compatible with a wide variety of other software and hardware. In addition, Buhl as a supplier had to be able to offer total-system integration responsibility. The IQ System meets all these criteria, says Bartholomew. He says a number of machinery suppliers have expressed interest in the system, which will also be offered for retrofitting.

A 'FRIENDLY' INTERFACE

The most immediately apparent distinction of the system is the look of the displays on the basic operator interface, the IQ Station. As part of Buhl's market research, the company asked, "What do machine operators hate?" They found that, for one thing, they hate paging through numerous screen displays in order to set up a machine. That's one reason Buhl went to a large CRT screen instead of a much smaller flat-screen display. Machine operators also hate to read text, Buhl found; so it developed a totally "object-oriented" interface.

What this means is that the machine can be set up and operated entirely from the touchscreen, using images or "objects," rather than words. Extremely realistic 3-D graphics replicate the familiar mechanical limit switches ("sliders"), "pots," and the like, which the operator can manipulate with a finger tip. For example, touching an image of a toggle switch would flip it from one position to another. Timers can be represented as a clock, temperature readouts as thermometers. To set up an injection speed/pressure profile or blow molding parison program, the user can "push" each slider to the desired position, watching the corresponding numerical readout change in a neighboring "window." Similarly, a line graph of a process profile could be altered by "dragging" the line up or down with a fingertip. Alternatively, a profile could be shown as a bar graph, and both the width and height of the bars--representing steps in the profile--could be altered by moving a fingertip across the screen. The customizing potential of the graphics display is said to be virtually unlimited.

Other novelties made possible by the high-resolution (1024 x 768 pixels) color monitor and XGA graphics board include the ability to accept digitized images. Thus, photographs of a machine or diagrams of hydraulic or electrical circuitry could be taken directly from a manual via a digitizing scanner. Such images could be highlighted with flashing signals to indicate the source of a problem during self-diagnostic routines. (Audible voice messages--e.g., "Warning, Zone 1. System shutdown, Zone 3"--can also be provided.) An operator could touch different parts of the machine or pieces of auxiliary equipment in order to initiate setup routines. Also, photos of acceptable and unacceptable parts could be scanned in for operators to use as q-c references. Even CAD drawings could be brought onto the screen and animated, if desired.

Standard software will also offer numerical displays of statistical process-control (SPC) data such as X-Bar & R charts, Cpk and standard-deviation values. User-configured reports on quality and production data, downtime, and operator attendance can be prepared at the terminal or at a remote supervisory host. The operator station can store one to two shifts worth of process and production data and also pass it on to the host at user-determined intervals. (The operator stations utilize the OS/9 operating system and are said to communicate equally well with IBM, Macintosh, DEC or other computers.)

The operator station can also accept input from electronic gauges, scales and bar-code readers. Messages can be sent to and from operators over the network via electronic mail. SPI communication protocol is available. Modem tech-service support capability is standard. In an age when travel has become so expensive, service personnel can pull up any screen display at a remote location, and even download a new program to a machine while it's running.

BUILT RUGGED

Two common drawbacks of CRT displays have been addressed. One is the annoying slowness with which some systems "re-paint" the screen with a new image or "page." This has been eliminated by a "distributed intelligence" architecture that limits the function of the operator station mainly to updating screen displays (it does have a limited PLC function), while control functions are performed elsewhere.

Reliability of CRTs in an industrial environment is another problem that has been addressed by a new and highly rugged design. The military-grade monitor is totally sealed and water-tight, encased in a one-piece aluminum die casting and a polycarbonate screen shield that's tough enough to withstand hammer blows, says Bartholomew. A floppy-disc drive to accept setup recipes is located behind a spring-loaded flap under the screen. The die-cast shell has rubber "bumpers" on it to prevent chipping when the monitor is swung around, and the mounting collar has vibration isolation mounts designed specifically to protect the monitor when mounted right on the machine. In addition, the mounting collar rotates 90 [degrees] and provides maximum flexibility for mounting on a horizontal arm, vertical stand, or table.

For those who desire one, an optional handheld cursor-control keypad for manipulating the screen display clips onto the side of the monitor when not in use. A second optional handheld device also clips onto the CRT terminal. This unit can be configured as a keypad with LCD display for use at stations where a CRT is not normally required; it can be connected by plug-in cable to the IQ System's control modules. Alternatively, the handheld pendant can be configured with pushbuttons for standard manual machine control. Thus, in the case of a machine retrofit, the manual controls can be replaced for a few hundred dollars instead of a few thousand as usual. Being able to carry manual machine controls around with you in a compact device "is a pretty radical idea," comments Bartholomew. It also means that a full machine control system with a handheld pendant as the operator interface could be supplied for as little as $5000-6000 ($9500 with closed-loop control). That compares with around $25,000 for a system with CRT display.

The IQ Station can be configured as a supervisory or host station by adding an optional 386-type personal computer in the form of a single board plus a 40- or 100-MB hard disc, which mounts in a tray in the bottom of the CRT housing. A supervisory CRT station costs around $15,000.

In addition, Buhl is offering separately the software for the IQ station to run on an IBM-compatible PC.

FLEXIBLE CONTROL HARDWARE

IQ System components are designed to communicate over a highspeed network--either an Ethernet bus type or token-ring version--using the standard TCP/IP protocol (more than 1500 times faster than the SPI standard, which is also available).

The actual machine control module, called the IQ Rack, has slots for 10 I/O boards or mated pairs of I/O and processor boards. One such rack is sufficient to control an injection molding cell, a four-head blow molder, or a sizable coextrusion system, says Bartholomew. I/O capacity is essentially unlimited, because multiple racks can be linked together.

The IQ Rack includes a regulated power supply for both the system itself and for field sensors--the latter, a reportedly unusual feature. The field wiring block, which accepts wire leads from sensors, connects to a base plate and that connects to the circuit boards in the rack. This feature allows the base plate to be unplugged so that a board can be replaced, without disconnecting any sensor leads.

Each "dumb" I/O carrier board in the Rack can be sandwiched together with a "smart" IQ Processor Board. Each smart board is a complete 10-MIPS (million instructions per second) microcomputer with three microprocessors, performing 32-bit signal processing at 36 MHz. One micro is a Motorola 68000, which performs sequencing and SPC/SQC monitoring of up to 40 variables.

The combination of a smart board and an I/O board can provide closed-loop, self-tuning PID control of any desired function. One smart board can also "talk" to several I/O boards. For example, one smart board can run an entire four-head blow molding machine with closed-loop PID servovalve parison control on each head.

This "distributed intelligence" approach allows the user to buy just as much control capability as he needs, and he can add to it easily as desired. It's also very fast. Communication within the Rack is by 20-MHz VME-Bus at 15 megabits/sec. Scan time for the controller is in microseconds, rather than milliseconds for many programmable logic controllers (PLCs).

Such speed, according to Bartholomew is required for many processes today, such as high-speed, thinwall injection and complex coextrusion lines or parison profiles. It also allows, for example, injection-speed profiles to be graphed on the CRT in real time, rather than on the next cycle.

The IQ controller is also said to be very simple to program, since Buhl developed a "state language," to replace conventional ladder logic. This language defines process states (such as injection or holding), and the transition between them defined by a process condition.

A further component of the IQ System is the IQ Block, essentially a small PLC consisting of a single smart board and fixed amount of I/O (configurable for four analog inputs, six thermocouples, eight digital inputs and eight outputs, four to eight heat/cool loops, speed encoders, or strain-gauge inputs). It comes with a plug-in, detachable, handheld keypad with 3 x 3 in. LCD display that can show graphics--i.e., trend charts. (It can also be linked to the network and run by a remote operator station.) SPI communication protocol is standard and Ethernet TCP/IP board optional.

As a stand-alone 10-MIPS computer costing $1800-6000, it can be used for controlling a gravimetric feeder, gear pump, dryer or blender. For $5000-6000, it can be configured as a complete low-end extruder control (motor speed, temperatures, and head-pressure loop) or complete closed-loop servovalve injection and clamp control. It can also serve as a protocol converter or LAN gateway for another controller, or can pre-format reports from other makes of injection-machine controller before sending them to the supervisory PC station. Another possible use would be as a production and process monitor, capable of supplying real-time process data for graphic display at a PC.

PHOTO : Outstanding graphics capability of Buhl's new IQ Series touchscreen CRT station allows scanning in digitized photographs, diagrams from a machine manual, or CAD drawings. Touching the appropriate part of the machine produces a setup screen for that function.

PHOTO : Realistic-looking 3-D graphics simulate tactile control hardware such as limit switches (which you can slide across the screen with your fingertip, as the profile graph changes below), dials, toggle switches, pushbuttons, etc. Operator can thus set up a machine without reading or typing anything.

PHOTO : IQ CRT is encased in a die-cast shell with a tough plastic screen guard. Detachable handheld cursor-control keypad is at right of screen; on left side of CRT is detachable, plug-in machine control keypad. At right is IQ Rack, which holds enough circuit cards to provide closed-loop control of any parameter on a complex coextrusion line, complete injection molding cell, or eight-head blow molding machine.
COPYRIGHT 1991 Gardner Publications, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1991, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

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Title Annotation:computer integrated manufacturing
Author:Naitove, Matthew H.
Publication:Plastics Technology
Date:Apr 1, 1991
Words:2038
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