| 摘要 |
PURPOSE:To stop securely a magnetic head on a recording medium by a CPU and to secure the control by a computer by informing a host computer of an abnormal moving of the magnetic head at the time of the runaway of a program. CONSTITUTION:When a magnetic head 3 moves further inside from the inner- most track position, an interrupter member 7 rotates counterclockwise due to the rotation of a pulley 5, and the optical path of a moving position limit sensor 9 is cut off. Thus a monostable multivibrator 21 is triggered owing to the fall that the output of an arithmetic amplifier 19 inverts from a high level to low one, and its output Q' resets a CPU11. Then the action of a stepping motor 16 is stopped, and further the shifting to the interior of the head 3 is stopped. When the output Q' is stopped, a monostable multivibrator 22 is triggered, and an offering signal is given to the CPU11. The interruption processing can check that the head 3 is positioned in the inner-most periphery, and the head 3 is shifted outside, whereby it can be prevented from colliding with a keep plate 2 of a disk 1. The CPU11 reports the abnormality of a program to a host computer. |
