| 摘要 |
In an apparatus for controlling extension and retraction of a shielding member, a bi-directional motor has a drive shaft coupled to the shielding member. A processing unit is operable in a normal operating mode, where the processing unit controls the motor for moving a free end of the shielding member between predetermined extended and retracted positions based on extended and retracted position information stored in a memory. When supply of electric power to the apparatus is interrupted, the processing unit determines current position information from motor rotation signals provided by a sensor unit such that the processing unit is able to automatically control the motor for moving the free end of the shielding member when supply of the electric power to the apparatus is resumed.
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