Working timeWorking (laboring) time is the period of time that a person spends at paid labor. Unpaid labor such as personal housework or caring for children or pets is not considered part of the working week. Many countries regulate the work week by law, such as stipulating minimum daily rest periods, annual holidays, and a maximum number of working hours per week. Working time may vary from person to person, often depending on economic conditions, location, culture, lifestyle choice, and the profitability of the individual's livelihood.
Closed-loop controllerA closed-loop controller or feedback controller is a control loop which incorporates feedback, in contrast to an open-loop controller or non-feedback controller. A closed-loop controller uses feedback to control states or outputs of a dynamical system. Its name comes from the information path in the system: process inputs (e.g., voltage applied to an electric motor) have an effect on the process outputs (e.g., speed or torque of the motor), which is measured with sensors and processed by the controller; the result (the control signal) is "fed back" as input to the process, closing the loop.
Differential analyserThe differential analyser is a mechanical analogue computer designed to solve differential equations by integration, using wheel-and-disc mechanisms to perform the integration. It was one of the first advanced computing devices to be used operationally. The original machines could not add, but then it was noticed that if the two wheels of a rear differential are turned, the drive shaft will compute the average of the left and right wheels.
Control valveA control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level. In automatic control terminology, a control valve is termed a "final control element". The opening or closing of automatic control valves is usually done by electrical, hydraulic or pneumatic actuators.
Current loopIn electrical signalling an analog current loop is used where a device must be monitored or controlled remotely over a pair of conductors. Only one current level can be present at any time. A major application of current loops is the industry de facto standard 4–20 mA current loop for process control applications, where they are extensively used to carry signals from process instrumentation to proportional–integral–derivative (PID) controllers, supervisory control and data acquisition (SCADA) systems, and programmable logic controllers (PLCs).
Internet of thingsThe Internet of things (IoT) describes devices with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other communications networks. The Internet of things encompasses electronics, communication and computer science engineering. Internet of things has been considered a misnomer because devices do not need to be connected to the public internet, they only need to be connected to a network, and be individually addressable.
ProfibusProfibus (usually styled as PROFIBUS, as a portmanteau for Process Field Bus) is a standard for fieldbus communication in automation technology and was first promoted in 1989 by BMBF (German department of education and research) and then used by Siemens. It should not be confused with the Profinet standard for Industrial Ethernet. Profibus is openly published as type 3 of IEC 61158/61784-1. The history of PROFIBUS goes back to a publicly promoted plan for an association which started in Germany in 1986 and for which 21 companies and institutes devised a master project plan called "fieldbus".
