A sensor element (10) has a circuit board (11), which has at least one plane having a printed coil (12). The printed coil (12) has at least one first via (15), which is arranged outside an outermost coil winding (13). A shielding ring (17) is arranged between the first via (15) and the outermost coil winding (13). An inductive sensor has several such sensor elements (10).

A proximity switch, comprising a coil arrangement including at least two receiving coils and at least one transmitting coil, and a control and evaluation unit arranged downstream of the coil arrangement, the control and evaluation unit being configured to obtain a switching signal when a target approaches a predefined response distance of the proximity switch. The at least two receiving coils and the at least one transmitting coil are planar coils and are arranged in a common coil plane being arranged completely within one single copper layer. The common coil plane is oriented perpendicular to a longitudinal axis of the proximity switch. The at least two receiving coils and the at least one transmitting coil do not overlap one another in the direction of the longitudinal axis and do not enclose one another circumferentially.

A sensor arrangement for determining at least one physical parameter of a sensor unit which is activated by at least one periodic excitation, comprising a detection region in which changes of the parameter in the surroundings of the sensor unit lead to an output signal from the sensor unit. The sensor unit is wired such that if there is no change of the parameter in the detection region the output signal is a zero signal at the output of the sensor unit, whereas if there are changes of the parameter in the detection region the output signal is a signal that is not zero and which has a specific amplitude and phase. By means of a closed-loop control, the non-zero signal in the receive path is adjusted to achieve an adjusted state at zero even in the presence of changes of the parameter in the detection region. Inherent in the control signal used for this adjustment is a deviation (x, y) of the control signal from the adjusted state, which deviation represents information about the parameter. To create a sensor arrangement and a method in which values of a physical parameter in a detection region can be clearly determined, in a four-quadrant representation of the deviation (x, y) in the form of a vector analysis in a phase space of the control signal, the angle of an imaginary vector (2.6) relative to the x axis of an x, y coordinate system, said vector leading from the origin (2.7) of the x, y coordinate system to a measuring point (2.5) and said origin corresponding to the adjusted state, represents a measurement for the change of the parameter along a direction, and/or the magnitude of the imaginary vector (2.6) represents a measurement for the change of the parameter along a further direction.

The invention relates to an inductive proximity sensor, comprising: a sensor coil; a pulse evaluation circuit which is configured to provide an excitation pulse for the sensor coil and to obtain a resulting voltage response; a control unit which is configured to to control the pulse evaluation circuit according to a pulse evaluation process such that the sensor coil is excited by an excitation pulse of a predetermined duration of time; to detect at least a first measurement voltage at a specific first point in time after providing the excitation pulse, and to provide an indication regarding the presence or absence of an object to be detected in a detection area around a sensor coil,
wherein a synchronization unit is provided in order to receive a synchronization signal which indicates if or when a pulse evaluation process is active in an adjacent proximity sensor, and in that the control unit is configured to start the pulse evaluation process in dependence on the synchronization signal.

An inductive proximity switch comprising signal oscillating circuit and a reference oscillating circuit; multiplexer circuit designed to alternately activate the signal oscillating circuit and the reference oscillating circuit; driver circuit having an oscillator designed to operate the activated signal oscillating circuit and the activated reference oscillating circuit with an oscillator frequency, respectively; detection module designed to determine a number of oscillations of the activated signal oscillating circuit measured within a predetermined gate time and a number of oscillations of the activated reference oscillating circuit measured within the predetermined gate time; and an evaluation module designed to determine a difference signal on basis of the determined number of oscillations of the activated signal oscillating circuit measured within the predetermined gate time and the determined number of oscillations of the activated reference oscillating circuit measured within the predetermined gate time, and to generate a control signal depending on the difference signal.

The flat-type proximity sensor detects a detection object in proximity to a plate-shaped member, and includes a head body, a cable, and an amplifier. The head body includes a case member, a coil, and a head board. The case member has a first surface and a second surface. The coil and the head board are accommodated in the case member, the first surface includes a detection surface, and the second surface is installed on the installation surface. The coil generates a magnetic field by applying a pulse-shaped excitation current. The head board includes a head circuit through which a detection current flows due to a change in a magnetic field. The cable guides the detection current from the head circuit to the amplifier. The amplifier includes a processing circuit that performs processing related to detection of the detection object based on the change in the detection current.

Techniques are disclosed relating to sensing an object using an inductive proximity sensor. In an embodiment, an apparatus includes a transmission coil having turns formed on a first circuit board and including a first primary winding having a first winding direction. The apparatus further includes a first sensor coil having turns formed on a second circuit board and including a second primary winding having a second winding direction and a second sensor coil having turns formed on a third circuit board and including a third primary winding having a third winding direction opposite to the second winding direction. The coils are spaced apart from one another in a common axial direction and at least one of the coils includes a compensation winding having at least one turn, where the compensation winding is arranged radially outside of, and has a winding direction opposite to, the same coil's primary winding.