At present, the PLC in machinery manufacturing, petrochemicals, iron and steel metallurgy, automobiles, light industry and other fields of application have been developed by leaps and bounds.

• 相反，排在下面的梯形图，其被刷新的逻辑线圈的状态或数据只能到下一个扫描周期才能对排在其上面的程序起作用。