Implementation Of Marine Crane Compound Control Based On PLC

Marine cargo crane for ocean ship is the most typical one of the deck machinery.If we can own the complete description of the existing electric cargo crane equipment and the quantitative information of the necessary performance,the work process of electric winch as a whole applies to Marine Engineering teaching courses,the realization of the true situation as far as possible to the integration of theory and practice,so that the electric cargo crane working principle,characteristics,and control the process is more intuitive.Marine electric cargo crane is composed of three major devices:HOISTING, LUFFING,SLEWING.HOISTING by MICROMASTER 440 and the AC asynchronous motor to realize;LUFFING by FM354 and AC servo motor to achieve; SLEWING by FM353 and the step motor to achieve.Based on the S7-300PLC marine electric cargo winch control system uses an advanced PROFIBUS technology,the frequency inverter,function modules,CPU,HMI(Human Machine Interface) TP270 together through a bus interconnect to achieve centralized control and management.Marine electric-power cargo crane compound control system based on PLC applies consecutive PID to the cargo HOISTING system,applies step-in PID to the foundation SLEWING system and applies pulse breadth modulated PID to the jib LUFFING system.The whole system has many functions such as smoothness start-up, three-stage auto brake system,reverse torque control,operation frequency limited,limit position protection,interlock and cargo falling off preventing,and instruction of the time between maintenance and inquiry of past parameter.The functional modules have many protections for the motor normal condition:undervoltage,overvoltage,overload, lack phase,so greatly simplifying the circuit.The whole system possesses high reliability and maintainability,flexibility and easy extension.TP270 interface display control process and information,to facilitate parameters modification and fault diagnose, so students can more conducive understand and accept ship power knowledge.