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World's First Microcomputer-Based Digital Controller

Digital control contributes to energy saving, pollution prevention, and productivity increases in all industries.

World's First Microcomputer-Based Digital Controller

Toshiba developed the TLCS-12 12-bit microcomputer as an electronic engine control for Ford Motors in 1973. The computer was designed for industrial applications such as process control, which required a measurement accuracy of 0.1%. In addition, it was equipped with a CPU and peripheral LSIs and was designed to withstand severe environmental conditions, including both temperature and humidity fluctuations. Engineers were pleased to learn that the size of the computer had been reduced to a palm-size unit.

The company soon launched an application development project for industrial control systems and in June 1975 successfully developed the world's first digital controller, named TOSDIC™, consisting of a conventional analog controller combined with a microcomputer.

Japanese industries expanded rapidly in the 1970s. As steel and petroleum production facilities became larger, more complicated plant operating systems were required in order to improve productivity, save energy, and prevent pollution. The demand for process computer-based digital control systems rapidly increased, because analog control required an individual controller to control each variable (e.g., temperature and flow rate). In the case of digital control, however, a problem in one computer could lead to the failure of the whole plant. Engineers therefore had to create a reliable system while keeping the economic efficiency of the facility in mind.

Digital controllers at the time were distributed systems consisting of a control station incorporating a microcomputer, and loop stations to monitor and operate up to eight control points. Since the digital controller was easier to use, monitor, and maintain than the previous system, the new system was accepted by industry as an innovative product surpassing the analog system in terms of reliability and economy. The controller was further developed into a one-loop controller in 1979, in which each of the loop stations was equipped with an embedded microcomputer.

The digital controller improved the quality of control of each control loop and was capable of performing complicated multivariable control. It was particularly useful in the combustion controls of boilers and reactors, as exemplified by the Double Cross Limit™ combustion control system that was developed to maintain the air/fuel ratio within the optimal combustion values, regardless of changes in combustion capacity. These systems contributed greatly to pollution prevention, energy saving, and productivity increases at industrial plants. The digital controller system was employed in most industrial sectors, including the iron and steel, petrochemical, thermal power generation, and water supply/sewage industries, and Toshiba received the Mainichi Industrial Technology Award for the controller in 1981.

In the 1980s, there was a growing need for high-mix, lowvolume production and flexible automation. To respond to these market requirements, Toshiba developed a CIE integrated control system called CIEMAC™, the term CIE being derived from a combination of computer (C), instrumentation (I), and electrical control (E). Technologies cultivated during digital controller development, including microelectronics, control, and information technologies, allowed microcomputers to be applied in other instrumentation equipment including rolling measurement instruments and electromagnetic flowmeters.

DIN-size one-loop controller  210D Series

DIN-size one-loop controller 210D Series

CIE integrated control system  CIEMAC ™

CIE integrated control system CIEMAC™

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