| 摘要 |
PURPOSE:To detect the abnormal operations of a reciprocating body with good accuracy by setting permissible upper, lower limit values with respect to the dead center value of the reciprocating body and the rate of change in the dead center value, and comparing the actually detected dead center value and the rate of the change thereof and the permissible values. CONSTITUTION:The movement of a reciprocating body is detected by using a magnetic sensor or the like, and the dead center value is detected and stored at every reciprocating motion. From the stored values thereof, the average value of the dead center value during the period when a reference value is set is operated, and a constant allowaance value is added to said value, whereby the permissible values for upper and lower limits are set and the values are stored. From the stored value of the dead center values, the max. value of the rate of change is operated and an allowance value is added thereto, whereby a permissible change value is set and the value is stored. During the period when abnormality is detected, the dead center values of the reciprocating motion are detected and stored in the same maner as mentioned above, and the rate of change is operated. When the rate of change obtained at every reciprocating motion is larger than the above-mentioned permissible change value, small abnormality is indicated and when the abnormality is larger, the dead center value exceeds the above-mentioned permissible upper and lower values. |
