50, 25, 10 Years Ago

Staff -- Control Engineering, 7/1/2004

This page offers a look back on a variety of interesting items from Control Engineering's past issues, highlighting content from 50, 25, and 10 years ago.

GE and IBM weld first link of computer network

Imagine a desk-sized computer as fast and as versatile as an IBM 701 or a RemRand Univac. None exist, nor are they likely to for quite a while. But General Electric has installed the next best thing.

The computing center of GE's Aircraft Gas Turbine Division (Evendale, OH) has a 701 running three shifts a day. Two other branches of GE (in Lynn, MA, and Schenectady, NY) funnel problems into this computer. Up to now they've been telegraphing problems and answers back and forth between Evendale and Lynn, and Evendale and Schenectady.

The plan is to turn this scramble into a tight network. The means is IBM's Electronic Data Transceiver, which transmits data over an ordinary telephone line. It can duplicate punched cards at the rate of 11 per minute.

The long-range implications of this setup are exciting. Transceiver networks may give smaller companies quick, reliable access to computers which they could not afford to rent or buy but which they might need for an occasional problem. Or a large company, with several scattered plants, could rely on one centrally located computer.

Using color in industrial control graphics

The color CRT display terminal is fast becoming a common component in sophisticated monitoring and control systems. In fact, together with some form of data highway, the color CRT is the essential ingredient of the snowballing trend toward distributed control systems. But color in CRT displays has sometimes unexpected effects on human observers. And color can multiply the information content of the display beyond quick comprehension if it is not used well.

Color graphics add multiple dimensions to a control display. Besides pictorializing a process, color can identify change in status and signal alarms. Besides showing valves opening, pumps operating, and tanks filling, colors can identify different process fluids. Color speeds identification, improves visualization, and reduces response time. Most important, color packs "at-a-glance" information in a single frame, helping the operator simultaneously monitor a greater number of critical parameters.

Marvin English, Sentrol Systems, says that today's system users have sophisticated expectations for video display systems. "They take color television for granted at home and expect to see color in the systems they use at work. Displays must use color in an attractive manner and profiles must be smooth without step effects."

CAN-based I/O system taps PC for machine control

Technological advances are quickly providing low-cost alternatives to machine control systems. A new product, named "Cutler-Hammer Control," interfaces a CAN-based I/O network of sensors and actuators to industrial control software packages running on a PC. The basic hardware element is an AT bus card manufactured by Cutler-Hammer. Called the "Bus Manager," it puts four CAN nodes into one PC expansion card slot.

Each CAN node consists of up to 16 clusters or junction boxes. The CAN electronics is in the junction box; ordinary sensors, switches, coils, etc., connect directly to it. Thus, it is unnecessary to purchase special sensors or other I/O devices with embedded CAN chips.

The basic I/O component of the cluster is the "cube." There are cubes for various combinations of "ins" and "outs," both discrete and analog. Cutler-Hammer customers may purchase printed circuit boards with appropriate connectors or they have the option of purchasing a complete junction box, with all of the electronics encased in a NEMA 4 enclosure.

Of course, putting a CAN chip in each device is more expensive, but Cutler-Hammer is considering this approach for special applications that provide added value to their customers.

In other July 1994 news...

Elsag Bailey acquires Fisher & Porter for $157 million.