Lifting equipment plays a key role in port operation, and is the core equipment of loading and unloading operation.
Its operational reliability and stability determine the efficiency of the whole port loading and unloading operation. In order to improve the comprehensive efficiency of equipment operation, the programmable controller is applied to it. Based on computer technology, through the effective integration of communication technology, control technology and lifting professional technology, the control flexibility and reliability of lifting equipment are improved, and the occurrence of operation failures is reduced, so as to improve operation efficiency. This paper briefly analyses the application method of programmable controller in port lifting equipment.
In order to effectively apply the programmable controller to port crane equipment, it is necessary to determine its characteristics. Based on the requirements of actual operation on the performance of crane equipment, the application direction and key points should be clearly defined in advance, and the purposeful research should be carried out. Through the research on the application technology of programmable controller, we strive to further improve the reliability and stability of crane equipment operation, make the equipment control more flexible, complete more difficult operations through accurate control, and promote the development of port crane equipment towards automation and electrification. The programmable controller mainly consists of power supply, calculator, memory, CPU, communication unit and input and output modules. Because of different brands, there are great differences in programming. When it is applied to the optimization of port crane equipment design, designers need to choose the most appropriate brand based on their actual needs and combined with their own practical experience in the past. Programming software of any brand of programmable controllers can basically work in the environment of WIN98 or WIN2000. The software runs in the way of menu prompting. According to menu prompting, it can complete various programming tasks, edit and modify them according to the actual situation, and at the same time, it can make some breakdown points in the compulsory program under the online state.
Processing [1]. Common programmable controller programming software can call other subroutines through one main program, program through statement table and ladder diagram, and convert and calculate various binary systems.
At the same time, integer arithmetic and floating-point arithmetic of various digits of timer, counter and high-speed counter are carried out. It can also detect and display code and fault name in time to improve the programming effect. The programmable controller is used to control the lifting height, speed and weight of the crane. At the same time, it can provide acceleration and deceleration, cross beam protection, overspeed protection and overweight protection for all parts of the crane, so as to improve the operation safety of the crane. That is to say, by inputting the digital signal of rotary encoder, data information such as lifting position and speed are monitored, and by inputting 4-20MA analog signal into the weight sensor, the weight is monitored. Finally, all operation instructions of the driver are completed by communication between PLC and frequency converter, and all operation operations are completed [2]. Like the lifting part, the car needs high frequency operation in the whole lifting equipment work. The use of programmable controller to control it can improve the accuracy, safety and rapidity of its action, which is of great significance to improve the accuracy of the operation. That is to say, the programmable controller and the huge and rigorous program are used to deal with various working conditions, driving the car forward and backward, calculating the running position, accelerating and decelerating operation, front and rear crossbeam protection, front and rear limit position protection and pitching mechanism interlocking, etc.
, to meet the operating requirements of container rapid transportation conditions [3]. Through the programmable controller to control and monitor the crane pitching mechanism action, determine the mechanism speed, position, acceleration and deceleration, and rise/fall position and other information, through the calculation of the command to complete automatic hooking and decoupling operation, thermostatic element improve the overall efficiency of the operation. At the same time, the speed and angle of the pitching mechanism can be monitored by the input signal of the rotary encoder to realize the over-protection of the operation. And through the program to control the solenoid valve of the pitching mechanism, improve the safety of operation. The structure of the cart is the crane running on the track, which is mainly responsible for fulfilling the operation requirements of container ships in different positions. The programmable controller is used to control the working process, drive the motor of the taxi mechanism, and drive the wheel to rotate, so as to promote the effective movement of the cart mechanism. At the same time, it can also monitor the motor speed of the car mechanism through the rotary encoder on the motor, and realize the limit position protection of the car left and right through the mechanical limit and infrared probe, and the anti-collision protection between the crane and the mast of the ship. In addition, for port crane equipment, the control of cable tension progress of cart reel is mainly realized by magnetic coupling on motor, and the cable tension progress is protected by limit switch. For the port crane mechanism, the braking requirements are usually set in the program, and then the hydraulic system is accurately controlled to ensure that the brake rail clamping operation and motor braking can be effectively realized. The control system of portal crane can be divided into mechanical system and electrical system. In order to improve the control effect, it is necessary to ensure a high coordination between mechanical and electrical parts.
Among them, the mechanical system includes lifting mechanism, carriage walking mechanism, rotating mechanism, portal frame, luffing mechanism, counterweight, track and so on. The structure is complex, self-important and difficult to adjust in the later stage. However, the operation accuracy is strict, and the precise control of each part is required.
Electrical system is to control each mechanism to ensure orderly and safe operation. Compared with mechanical system, software programming of electrical system has higher flexibility. It can achieve control purpose without changing hardware, and can effectively remedy the shortcomings of mechanical system. Based on the characteristics of portal crane control system, there are many control objects, including contactor, circuit breaker, frequency converter, relay, etc.
In order to reduce the complexity of control cabinet, the control quantity can be increased appropriately, such as PLC distribution protection cabinet, amplitude control cabinet, hoisting control cabinet, rotary control cabinet and walking control cabinet. The CPU mainframe is installed in the PLC power distribution protection cabinet to protect the power distribution of the system, and a rack is also installed in other control cabinets for the control of the corresponding institutions. In the driver’s cab, the control rod and button on the linkage table can effectively control the gantry crane mechanism. In order to reduce the number of cables in the driver’s cab, a rack is also needed to be extended internally for the output and input of various signals. The open network system is divided into three parts: control layer, information layer and equipment layer. Industrial Ethernet technology is used to collect data from PLC stations in order to achieve data aggregation and remote operation monitoring effect. The middle layer mainly applies the controller network, which is responsible for the exchange and control of data between PLC and computer. The underlying equipment mainly uses CompoBus/D or CompoNet network, which can connect all kinds of field equipment directly with PLC controller, collect data from different manufacturers and field, and configure and monitor them.
Through Fieldbus network, the effective connection between intelligent devices and controllers such as industrial field sensors, photoelectric switches, measuring instruments can be realized, and I/O data can be collected remotely to achieve the purpose of centralized control. Taking CompoBus/D bus network as an example, it can realize the effective connection of long-distance equipment in the control system, and it has the characteristics of low cost and high efficiency in practical application.
Hi Love can support multiple communication modes, and its application is more flexible. It is required to have remote I/O communication function and information service function, that is, the master station can read all slave station I/O information effectively and realize remote monitoring of I/O. To apply the programmable controller to the optimization design of port crane equipment, it is necessary to determine the application direction and technical points based on the operation principle of the crane equipment, so as to satisfy the actual operation requirements, make a good design plan, and realize the effective control of port crane equipment institutions through the effective application of computer technology and communication technology. System.