Abstract: A transmitter device for a sensor device detects a magnetic field change caused by an object approaching or moving past the sensor device, in particular by a wheel of a rail vehicle. The transmitter device has at least two alternating-current-fed transmitter oscillating circuits. In order to implement error disclosure of the sensor device in a particularly simple manner, the at least two transmitter oscillating circuits are formed in such a way that the resonance frequencies thereof are different from each other. A sensor device and a method for detecting a magnetic field change are also provided.

Abstract: A transmitter device for a sensor device detects a magnetic field change caused by an object approaching or moving past the sensor device, in particular by a wheel of a rail vehicle. The transmitter device has at least two alternating-current-fed transmitter oscillating circuits. In order to implement error disclosure of the sensor device in a particularly simple manner, the at least two transmitter oscillating circuits are formed in such a way that the resonance frequencies thereof are different from each other. A sensor device and a method for detecting a magnetic field change are also provided.

Abstract: A wheel sensor that is particularly suited for track release signaling systems has at least one sensor device having an AC-fed sensor coil of an electric oscillating circuit sensitive to an inductive interaction of the sensor coil with passing wheels of rail vehicles. A further spool is connected to the sensor coil for suppressing external interference fields in a counter circuit. The further coil is arranged underneath the sensor coil and a spacing distance between the further coil and the sensor coil is at least one third of the inside diameter of the sensor coil.

Abstract: An inductive sensor device for detecting a magnetic field change caused by an object approaching in the region of an influencing side of the inductive sensor device includes at least one coil system having a transmitting coil fed with alternating current and first and second receiving coils. The two receiving coils are connected in series in opposite senses, the first receiving coil is disposed in front of the transmitting coil and the second receiving coil is disposed behind the transmitting coil, relative to the influencing side. A screen is provided behind the second receiving coil relative to the influencing side. An inductive proximity sensor with an inductive sensor device is also provided.

Abstract: A wheel sensor that is particularly suited for track release signaling systems has at least one sensor device having an AC-fed sensor coil of an electric oscillating circuit sensitive to an inductive interaction of the sensor coil with passing wheels of rail vehicles. A further spool is connected to the sensor coil for suppressing external interference fields in a counter circuit. The further coil is arranged underneath the sensor coil and a spacing distance between the further coil and the sensor coil is at least one third of the inside diameter of the sensor coil.