A system or piece of computer code in which every step in a control mechanism is contained inside the system, and does not utilize external input See also Feedback
refers to an advanced version of the Dichromat colour heads in which the system automatically detects and corrects for changes in the colour and intensity of the lamps, and movement of the filters is microprocessor controlled This system provides highly accurate filtration settings and maximum print repeatability through lamp changes and when working from recorded exposure data The need for fewer test prints ensures greater productivity
An underground heat exchanger piping system usually of polyethelene or polybutylene designed to allow the extraction or rejection of heat to the earth by the circulation of fluid within the tubing
A method of designing a control or guidance system in which all the elements (sensors, computers, actuators, etc ) are linked in such a way as to operate continuously with feedback between the elements The guidance systems for Apollo spacecraft were closed loop systems
A system in which each component is connected to the next component with the last component being connected to the original device Forms a complete circle
Checks that the machine has or has not obeyed the computer command {See Open Loop & Feedback}
A system in which the output of one or more elements is compared to some other signal to provide an actuating signal to control the output of the loop
An operating mode of the PCM enabling modification of pre-programmed instructions based on a feedback system By constant exhaust sampling, a closed loop system allows pre-programmed engine adjustments to occur while running in order to minimize exhaust emissions
A control system that uses a sensor to measure process variable and makes decisions based on that input
A means of operating a control surface by means of flexible wires, under tension, attached to either side; sometimes known as pull-pull
A regulator circuit in which the actual value of the controlled variable (such as pressure, temperature or speed) is sensed and a signal proportional to this value (feedback signal) is compared with a signal proportional to the desired value (set point signal) The difference between these signals (error signal) causes the controlling device to change in the direction that will reduce the difference in signals to zero