Control System Design Of Bulk Grain Transshipment Flow Based On PLC

China is a populous nation, grain storage and transportation is vital to national economy and people’s livelihood. The intellectualization of the control system has become a hotspot in the research of bulk grain control. Based on the hardware layout, control network, control system foundation of Beiliang Port’s PLC control system, this paper optimizes the function of this transportation system, uses the characteristic of automated bulk grain transfer process, carries out the design of automatic process selection and variable flow control for bulk grain system, realizes the unattended operation for bulk grain system.By using PLC, HIM human-computer interface and some related equipments, ControlLogix5500two-dimensional array as the temporary storage for process information, make all the equipments correspond to a binary number. When select the process, select the first and final equipment, list out a batch process according to the set process, and then determine the only work process by further choosing the middle equipments. Then compare the binary number which produced in the process with the corresponding relations in the temporary storage, the only process would be determined after all the comparison. The related equipment has been selected, inspect the equipment start-up and occupy status automatically. Then start the corresponding process after inspection and realize the automatic process selection of professional bulk grain control system.Using PLC control system, belt scale, valve opening apparatus, and related hardware devices, the flow control instruction issued by controllers would be sent to the work site components through PLC digital/analog conversion module. To collect the real-time flow information of the belt scale, adjust the electric valve opening at the bottom of the granary automatically, and switch the feedback information into digital quantity through conversion module, transmit to the HMI human-computer interface of control room by PLC and finally realize the grain flow variable control of the bulk grain system.System test proved that the system designed in this paper has reached the expected effect achieved the function of automatic process selection of transportation system and grain flow variable control. It could meet the production needs, enhance the production and management level of the whole control system, ensure the safety of the working site, reduce the work intensity of the field staff, and reduce the grain loss in transport links. It is a great improvement for the whole control system of Beiliang Port, and basically realized the unattended operation and automatic control.