| 摘要 |
PROBLEM TO BE SOLVED: To calibrate sensitivity of a magnetic sensor array regardless of a differential type/absolute value type.SOLUTION: Metal balls 2 smaller than a distance between adjacent magnetic sensors b are moved along an arrangement of the magnetic sensor b near a magnetic sensor array 1 where a plurality of magnetic sensors b detecting changes of an AC or DC magnetic field implied to a metal steel material are arranged, and gain of the respective magnetic sensors b is adjusted so that each measured value outputted when the metal balls 2 pass near the respective magnetic sensors b becomes a value in accordance with known value, and the sensitivity is calibrated. The metal balls 2 use air pressure and pass inside an air pipe 3 composed of a material that does not react to the magnetic sensors b. The air pipe 3 may be installed near a surface facing the metal steel material of the magnetic sensor array 1 or installed near a surface different from the surface facing the metal steel material. In the magnetic sensor array 1, the adjacent magnetic sensors b may be differential-connected.SELECTED DRAWING: Figure 2A |
