This system uses Schneider Premium – type PLC for the whole machine. Low – voltage electrical components are Schneider products, and ABB frequency converters are adopted. The movable beam hoisting mechanism uses the conventional method of rotor series frequency – sensitive resistance for speed regulation. The gantry motors are driven by two frequency converters respectively and are equipped with encoders, which can realize automatic or manual deviation correction of the gantry. The bucket – wheel trolley and the hoisting mechanism are respectively equipped with encoders, which can achieve fully automatic stacking and semi – automatic reclaiming operations. The fault monitoring system consists of a PLC and a GP2500S touch screen, forming a user – friendly man – machine interface.