There are a total of four ship unloaders in this set. The whole machines adopt the Siemens 6SE70 multi – drive system. The system uses the energy feedback method, eliminating the need for braking resistors. It is equipped with two parallel rectifier/feedback units, operating in a 12 – pulse mode. One inverter is used for each of the hoisting support and opening/closing mechanisms, and the closed – loop vector control mode is selected as the control mode. One inverter drives the trolley mechanism. The luffing mechanism and the trolley mechanism share one inverter through switching, and both mechanisms adopt the closed – loop vector control mode. One inverter drives the gantry mechanism, using the open – loop control mode.
The operation of the driver’s cab and the hopper vibrator both use Siemens M440 series frequency converters, and the motors of other auxiliary mechanisms are all directly started. The whole – machine control system uses Siemens S7300 series PLC with a modular structure. This system is equipped with a main station in the electrical room and a slave station in the driver’s cab. The communication control mode between the main station and the slave station is Profibus – DP. A 10 – inch color touch screen GP2500S is installed near the control console to monitor the operation status of the whole machine and display faults.
The control system can realize functions such as automatic grab operation, automatic and semi – automatic luffing unloading. It communicates with the host computer through the PLC Ethernet module and the external Ethernet switch. This machine is equipped with a CMMS system, which can dynamically display the position status of the trolley and hoisting mechanism, equipment fault alarms, and the status of various limit switches in real – time, achieving real – time fault detection. At the same time, it records historical faults and provides information for guiding fault – solving.