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【简答题】
设计一个用 PLC 控制的双头钻床的控制系统。 (1) 双头钻床用来加工圆盘状零件上均匀分布的 6 个。操作人员将工件放好后,按下启动按钮,工作被夹紧,夹紧后压力继电器为 ON ,此时两个钻头同时开始进给加工。大钻头到设定的深度( SQ1 )时,钻头上升,升到设定的起始位置( SQ2 )时,停止上升;小钻头钻到设定深度 (SQ3) 时,钻头上升,升到设定的起始位置( SQ4 )时,停止上升。两个都到位后工件旋转 120 °,旋转到位时 SQ5 为 ON ,然后开始钻第 2 对。 3 对都钻完后工件松开,到位后 SQ6 为 ON ,系统返回初始位置。 (2) 具有紧急停止。
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