60th Anniversary: CE History from 60, 30, and 15 years ago on computers, better automation software, and open systems
Happy 60th, Control Engineering! Help us celebrate by looking at issues from 60, 30, and 15 years ago. Control Engineering magazine first published in September 1954. This monthly column in 2014 will review coverage in issues 60, 30, and 15 years ago. While technologies have progressed since then, topics below (digital computers, computer control systems, process control open systems) remain relevant today.
September 1954: What computers promise
Giant digital computers, handling an increasing share of office work or solving overwhelming technical problems, are often compared with regiments of clerks wielding pencils or battalions of engineers brandishing slide rules. The analog computers, steadily finding new jobs in process control, are likened to human operators with the eyes of Argus and the limbs of a millipede.
Comparisons of this sort are generally misleading. Computers are information processing devices. They perform long series of elementary logical and arithmetical operations on information and condense it to useful forms. As such, computers complement man’s deductive processes. Merely equating their speed with human bustle gives computers both less and far more than their due. Mechanical and electronic "brains" cannot compete with the human mind’s scope, capacity, flexibility, or adaptability.
September 1984: Hierarchical computer control systems: Automating the planning process
When F.P. Brooks wrote the "Mythical Man Month," he compared the current software development process to the La Brea Tar Pits in Los Angeles. He presented his recommendations for the management of the development of large systems as a "boardwalk across the tar." He also said, "Show me your flow charts and conceal your tables, and I shall continue to be mystified." It seems tables make good bridges while flow charts make tar.
The methods used for the production of process control software are not improving quickly enough to keep up with the expanding needs of American industry. We are going to have to construct more than a temporary boardwalk in the case of industrial automation. What we need is a good modern steel bridge. The bridge we require will be composed of efficient software tools that display the structure and function of software in exactly the same way a good blueprint describes the structure and function of a bridge.
September 1999: Open systems in process control: Are they the answer?
Finding a single definition for the term "open system" is a thorny problem. In an open system, control engineers should be able to take appropriate control hardware (sensors, controllers, PCs, cabling, etc.) and software (any standard platform should do) and assemble the control application required to run a process plant.
Consensus among process control suppliers came slowly, taking most of the 90s to implement. As customers demanded open system benefits, evolutions of the true open system (and its unique definition) became unstoppable.
According to the "ISA Comprehensive Dictionary of Measurement and Control," 3rd Ed., an open system is defined as one "that complies with the requirements of the OSI (open system connection) reference model in its communication with other open systems." Fitting into and working within the thorns of this definition varies among the control system suppliers, however.
– 2014 edits, to fit this page, by Chris Vavra, content specialist, CFE Media.