| 摘要 |
PROBLEM TO BE SOLVED: To control a stroke changing speed by a simple method and enhance controllability of a cylinder. SOLUTION: A starting position and an end position of a piston 31 are detected by magnetic sensors 34a, b, a starting time and an ending time are recognized on the basis of this detection, and an actual time for the piston 31 to move from the starting position to the end position is found based on a difference between the starting time and the ending time. A range of allowable time for the piston 31 to move from the starting position to the end position is preliminarily stored in a memory 42. An alarm signal is generated when the actual time is outside of the range of the allowable time. A sensor is interposed between the starting position and the end position to allow both high level of controllability and correction of a moving speed. |
