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  2. Current loop - Wikipedia

    en.wikipedia.org/wiki/Current_loop

    Note that a 4-wire instrument has a power-supply input separate from the current loop. Panel mount displays and chart recorders are commonly termed "indicator devices" or "process monitors". Several passive indicator devices may be connected in series, but a loop must have only one transmitter device and only one power source (active device).

  3. Control loop - Wikipedia

    en.wikipedia.org/wiki/Control_loop

    A control loop is the fundamental building block of control systems in general and industrial control systems in particular. It consists of the process sensor, the controller function, and the final control element (FCE) which controls the process necessary to automatically adjust the value of a measured process variable (PV) to equal the value of a desired set-point (SP).

  4. Highway Addressable Remote Transducer Protocol - Wikipedia

    en.wikipedia.org/wiki/Highway_Addressable_Remote...

    The HART Communication Protocol (Highway Addressable Remote Transducer) is a hybrid analog+digital industrial automation open protocol. Its most notable advantage is that it can communicate over legacy 4–20 mA analog instrumentation current loops, sharing the pair of wires used by the analog-only host systems.

  5. Instrumentation in petrochemical industries - Wikipedia

    en.wikipedia.org/wiki/Instrumentation_in...

    Instrumentation comprises sensor elements, signal transmitters, controllers, indicators and alarms, actuated valves, logic circuits and operator interfaces. An outline of key instrumentation is shown on Process Flow Diagrams (PFD) which indicate the principal equipment and the flow of fluids in the plant.

  6. Closed-loop controller - Wikipedia

    en.wikipedia.org/wiki/Closed-loop_controller

    The control action is the switching on/off of the boiler, but the controlled variable should be the building temperature, but is not because this is open-loop control of the boiler, which does not give closed-loop control of the temperature. In closed loop control, the control action from the controller is dependent on the process output.

  7. Anti-submarine indicator loop - Wikipedia

    en.wikipedia.org/wiki/Anti-submarine_indicator_loop

    There were no allied vessels in the harbour so the indicator loops on the minefields were activated. Two hours later, at 23:32, current was detected in an indicator loop laid in a remotely controlled minefield, induced by the submarine as it passed over the cable. Activation of the loop detonated mines in the field, sinking the submarine. [10]

  8. Loop performance - Wikipedia

    en.wikipedia.org/wiki/Loop_performance

    Loop performance in control engineering indicates the performance of control loops, such as a regulatory PID loop. [1] Performance refers to the accuracy of a control system's ability to track (output) the desired signals to regulate the plant process variables in the most beneficial and optimised way, without delay or overshoot.

  9. Classical control theory - Wikipedia

    en.wikipedia.org/wiki/Classical_control_theory

    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.