the sensor operates at a heartbeat detection frequency of 16 times per second, which increases to 64 times per second when the signal is detected to change, taking into account low power consumption and real-time performance.
the main coil sends -- pulses in a working cycle, and the four coils present an x structure connected in the middle. because the reflected steel sheet is a semicircular structure, the signals sensed by the four coils are different at different positions. the impedance transformation part is connected to the same impedance transformation drive signal through a phase inverter. the result is that the impedance transformation of the left and right sides in a cycle is distributed in the upper and lower half cycles, the upper and lower arms are connected in pairs. in fact, such a structure divides a detection cycle into four detection time periods. the signal that finally enters the detection part can effectively reflect the position information of the steel plate.
theoretical basis for resisting magnetic field interference:
strong magnetic field is divided into static magnetic field and alternating magnetic field. the static magnetic field does not generate current on the coil and steel sheet, so it will not interfere with the whole system. the alternating magnetic field can generate current in the coil. because the four coils are connected at the same end and floating in the air, the current generated in each coil is mutually offset, so it will not interfere with the coil. the interference to the main coil is driven by the capacitance of the main coil and internal circuit, therefore, it can also be said that it is isolated and will not affect the internal circuit.