The invention relates to a sensor for determining an output value, the sensor having: a detection unit configured to detect a sensor signal; a preprocessing unit configured to determine an intermediate signal on the basis of the sensor signal and of a predefined reference signal; and an evaluation unit that is trained in accordance with a machine learning method and that is configured to determine the output value on the basis of the intermediate signal.

A proximity sensor for detecting non-contact detection of a target using a fiber optic strain sensor and a system for operating multiple such proximity sensors is disclosed. The proximity sensor includes an optic fiber that has an optic fiber strain sensor that is coupled to a mass that moves in response to the target. The mass can be a magnet that moves when a ferrous target is within the magnetic field of the magnet causing the magnet to move and apply strain to the optic fiber strain sensor. The optic strain sensor can include periodic variation in the refractive index of the optic fiber, such as a fiber Bragg grating. The proximity sensor can include a second fiber optic sensor that is sensitive to temperature or a second fiber optic strain sensor coupled to a second magnet that operates in opposition to the first magnet. A system coupling multiple proximity sensors can include an interrogator that has an optical power source and a detector, each coupled to a processor. The processor compares frequency information from the proximity sensor to a threshold to determine whether a target is in proximity to its corresponding proximity sensor.

A multi-measurement apparatus using a search-coil type sensor includes: sensor modules, each of which has one or more sensors including respective housings having respective inner spaces, respective cores formed to be inserted into the inner spaces of the housings, and respective coils which are each wound around a portion of an outer circumferential surface of each of the housings, the portion corresponding to a position of each of the cores; impedance matching units that are connected to a plurality of the sensors, respectively, and perform impedance matching; and amplifiers that are connected to the impedance matching units, respectively, and amplify a fine current and voltage generated during approach of objects to the sensors.

A proximity switch is disclosed. In an embodiment, the proximity switch has a defined detection range and includes an oscillator, an oscillator amplifier, a temperature sensor, a microprocessor and a storage medium. The oscillator generates an alternating magnetic field and changes its oscillation state as a result of a target entering the detection range. The oscillator amplifier is configured to be controllable in an open-loop and closed-loop manner and has at least one amplifier stage. In this embodiment, the at least one amplifier stage has a controllable temperature compensation circuit which is configured to influence the oscillation behaviour of the oscillator based on compensation values received as control data from the microprocessor and/or from the storage medium, depending on a temperature detected by the temperature sensor. The disclosed embodiments also encompass a method for operating a proximity switch with temperature compensation.