| 摘要 |
PURPOSE:To improve the reliability of blocking function, by stopping a drive motor urgently when a deviation between a relative rotating angle detected value of an encoder and an absolute rotating angle detected value of a potentiometer exceeds a permissible value. CONSTITUTION:A counter 20 is reset when an arm is in the reference attitude, counts a pulse train 100 from an encoder 18 when the rotation is started and outputs a relative rotating angle detection value 102. An analog detection value 116 of the absolute rotating angle of a drive motor 10 detected at a potentiometer 38 is taken as the absolute rotating angle detection digital value 114 at an AD converter 40. The two detection values are inputted to a comparator 42, an open instruction 110 and a close instruction 112 are outputted to contacts 32, 34 when the deviation 118 exceeds a permissible value 109, to stop the motor 10 and to activate a brake 36. Thus, the servo failure blocking function is improved. |
