| 摘要 |
PURPOSE:To obtain measured value with a high accuracy alone by eliminating measured value involved when a mobile electrode moves at an abnormal speed. CONSTITUTION:A transmission electrode 10 is formed as mobile electrode. The movement of the mobile electrode is determined by detecting an electrostatic capacitance signal from a reception electrode 14 with a cycle detection circuit 18 and integral analysis of the phase of the signal thus detected with an arithmetic circuit 19. A cycle decision circuit 20 is provided to determine the abnormality of cycle of the electrostatic capacitance signal detected. The cycle decision circuit 20 is provided with a direction discriminating means to detect the moving direction of the mobile electrode. The maximum cycle limit value and the minimum cycle limit value are set for the electrostatic capacitance signal and an alarm signal is outputted when the moving speed of the mobile electrode exceeds the limit value. |
