control systems
The Columbia Encyclopedia, Sixth Edition | Date: 2008
control systems combinations of components (electrical, mechanical, thermal, or hydraulic) that act together to maintain actual system performance close to a desired set of performance specifications. Open-loop control systems (e.g., automatic toasters and alarm clocks) are those in which the output has no effect on the input. Closed-loop control systems (e.g., thermostats, engine governors, automotive cruise-control systems, and automatic tuning control circuits) are those in which the output has an effect on the input in such a way as to maintain the desired output value. A closed-loop system includes some way to measure its output to sense changes so that corrective action can be taken. The speed with which a simple closed-loop control system moves to correct its output is described by its damping ratio and natural frequency. A system with a small damping ratio is characterized by overshooting the desired output before settling down. Systems with larger damping ratios do not overshoot the desired output, but respond more slowly. See feedback .
Author not available, CONTROL SYSTEMS.,
The Columbia Encyclopedia, Sixth Edition 2008
The Columbia Encyclopedia, Sixth Edition. Copyright 2008 Columbia University Press
Related newspaper, magazine, and journal articles from HighBeam Research
|
Critical Infrastructure Protection: Challenges in Securing Control Systems.
General Accounting Office Reports & Testimony; 11/1/2003; 397 words
; GAO-04-140T October 1, 2003 Computerized control systems perform vital functions across many of our nation's critical infrastructures. For example, in natural gas distribution, they can monitor and control the pressure and flow of gas through pipelines; in the electric power industry, they can
Read more
|
|
|
Critical Infrastructure Protection: Challenges and Efforts to Secure Control Systems.
General Accounting Office Reports & Testimony; 5/1/2004; 349 words
; GAO-04-628T March 30, 2004 Computerized control systems perform vital functions across many of our nation's critical infrastructures. For example, in natural gas distribution, they can monitor and control the pressure and flow of gas through pipelines. In October 1997, the President's Commission on
Read more
|
|
Control systems cyber security: terrorist threats, hackers, disgruntled employees, and vulnerable process control systems in highly volatile industries give plenty of cause for concern. Should voices calling for greater security be heeded, or are they just the cries of modern-day Chicken Littles?(Cover Story)
Control Engineering; 2/1/2005; Singer, Bryan L. Weiss, Joe; 2378 words
; ... technology (such as appropriately configured firewalls). Industry response Control systems security is a real concern. Is it all bad news? Not necessarily. Involving those who know control systems is key. ISA and other standards bodies are actively engaged in developing ...
Read more
|
|
|
Critical Infrastructure Protection: Multiple Efforts to Secure Control Systems Are Under Way, but Challenges Remain.
General Accounting Office Reports & Testimony; 1/1/2008; 681 words
; GAO-07-1036 September 10, 2007 Control systems--computer-based systems that monitor and control sensitive processes and physical functions--perform vital functions in many of our nation's critical infrastructures, including electric power, oil and gas, water treatment, and chemical production. The
Read more
|
|
On-Line Tool to Boost Implementation of Energy Sector -- Roadmap for Control Systems
U.S. Newswire; 3/13/2007; 484 words
; To: ENERGY EDITORS Contact: Process Control Systems Forum Secretariat, +1-877-727- 3674, secretariat@pcsforum.org WASHINGTON, March 13 /PRNewswire-USNewswire/ -- Attendees at the 2007 Meeting of the Process Control Systems Forum in Atlanta today witnessed the launch of an innovative, web-based tool
Read more
|
|
Unicom, ASME create Control Systems Expo. (News and Trends).
Fuel Oil News; 2/1/2003; 334 words
; Unicomm, LLC, and the American Society of Mechanical Engineers have announced the launch of the Control Systems Expo, the industry's first and only event designed to meet the changing needs of designers and engineers tasked with incorporating advanced automation into discrete systems, machines and
Read more
|
|
|
Chromalox survey projects more control systems with built-in diagnostics, predictive maintenance.(NEWS)(Brief Article)
Control Engineering; 4/1/2005; 271 words
; Pittsburgh, PA -- Most active users of temperature and power control systems are planning to integrate digital control systems that include built-in diagnostic and predictive maintenance functions along with remote PC access, according to 150 respondents to Chromalox's annual market trend study.
Read more
|
|
|
Information Security: TVA Needs to Address Weaknesses in Control Systems and Networks.
General Accounting Office Reports & Testimony; 6/1/2008; 763 words
; GAO-08-526 May 21, 2008 Securing the control systems that regulate the nation's critical infrastructures is vital to ensuring our economic security and public health and safety. The Tennessee Valley Authority (TVA), a federal corporation and the nation's largest public power company, generates and
Read more
|
|
Levers of Control. (book on innovative control systems in companies)
Internal Auditor; 10/1/1996; English, Denise M.; 727 words
; Total quality, empowerment of employees, and process reengineering -- all popular themes in today's organizations -- suggest that traditional controls may no longer be appropriate. In Levers of Control, Harvard Business School professor and author Robert Simons takes a shot at questions about how
Read more
|
|
Research Frontiers Licenses SPD Light-control Film Technology to SPD Control Systems.(Brief Article)
Wireless News; 10/31/2005; 291 words
; WIRELESS NEWS-(C)1999-2005 10Meters - http://www.10meters.com Research Frontiers announced that it has granted a non-exclusive worldwide license ...
Read more
|
Related entries from encyclopedias, dictionaries, and thesauruses
|
control systems (managerial)
A Dictionary of Sociology
control systems (managerial) See TRUST AND DISTRUST .
Read more
|
|
control system
Britannica Concise Encyclopedia
... caused to vary in a prescribed way. Control systems are intimately related to the concept ... a changing load. In World War II, control-system theory was applied to anti-aircraft batteries and fire-control systems. The introduction of analog and digital ... much greater complexity in automatic ...
Read more
|
|
|
AWACS (Airborne Warning and Control System)
Britannica Concise Encyclopedia
Mobile, long-range radar surveillance-and-control centre for air defense. Used by the U.S. Air ... against enemy planes. AWACS (Airborne Warning and Control System) AWACS (Airborne Warning and Control System) AWACS (Airborne Warning and Control ...
Read more
|
|
Guidance and Control Systems
Space Sciences
Guidance and Control Systems Guidance and control systems determine and regulate everything from the trajectory ... individual components that constitute guidance and control systems. Piloted and Unpiloted Guidance In piloted spacecraft ...
Read more
|
|
|
Reaction Control Systems
Space Sciences
Reaction Control Systems The space shuttle has a forward reaction control system (RCS) located in the nose of ... deactivated at that point. Reaction Control Systems are also employed on satellites and ... of the major companies providing RCS systems commercially for space applications ...
Read more
|