| 摘要 |
PURPOSE:To eliminate a trouble due to the operation error of an operator by receiving a radio wave from a transmitter carried by a B-board operator and detecting whether the operator is present or absent. CONSTITUTION:A receiver 111 is provided in a B-board 110, a transistor 112 as the detecting part to detect whether a B-board operator is present or absent is connected to to output side of the above-mentioned receiver 111 and the output side of the transistor 112 is connected through a photocoupler 102 of a device main body 100 to a central control unit 101. When a B-board operator 113 is engaged in the relaying work, the radio wave of a constant level enters the receiver 111 from a transmitter 120 carried the operator 113, and the receiver 111 operates a transistor 212 through an internal control circuit. While the operator leaves a seat since, the level of the receiving radio wave is low and is the threshold level or below of the receiver 111, the transistor 212 comes to be the recovering condition. The central control unit 101 does not hinder the exchanging processing accompanying the leaving of the seat of the B-board operator based upon the information.
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