'''Instrumentation and control engineering''' is a [[List of engineering branches|branch of]] [[engineering]] that studies the measurement and control of [[process variable]]s, and the implementation of such control to design [[system]]s. It combines two branches of engineering. [[Instrumentation#Instrumentation engineering|instrumentationInstrumentation engineering]] is the science of the measurement and control of the [[process variable]]s within a production or manufacturing area.<ref>[http://www.nait.ca/program_home_78211.htm "Instrumentation "], ''The Northern Alberta Institute of Technology.'', Retrieved 17 October 2012.</ref> Process variables include [[pressure]], [[temperature]], [[humidity]], [[Fluid dynamics|flow]], [[pH]], [[force]], and [[speed]]. Meanwhile, [[control engineering]], also called control systems engineering, is the engineering discipline that applies [[control theory]] to design systems with desired behaviors. Control engineers are responsible for the research, design, and development of control devices and systems, typically in manufacturing facilities and [[Oil production plant|process plants]]. Control methods employ sensors to measure the output variable of the device being controlled and provide feedback to the controller so that it can make corrections toward desired performance. When a device is designed to perform without the need of human inputs for correction, such as cruise control for regulating a car's speed, it is called automatic control. Control systems engineering activities are multi-disciplinary in nature. They focus on the implementation of control systems, mainly derived by mathematical modeling of systems of a diverse range. Because instrumentation and control play a significant role in gathering information from a system and changing its [[parameter]]s, they are a key part of [[control loop]]s.
