There are a total of eight ship unloaders in this project. The entire machines are equipped with Siemens 6SE70 multi – drive systems, which adopt an energy feedback mode, eliminating the need for braking resistors. Two parallel rectifier/feedback units are provided, operating in a 12 – pulse mode.
For the hoisting support and opening/closing mechanisms, one inverter is used for each, and the closed – loop vector control mode is selected. The trolley mechanism is driven by one inverter. The luffing mechanism shares one inverter with the trolley mechanism through switching, and both mechanisms adopt the closed – loop vector control mode. The gantry mechanism is driven by one inverter with an open – loop control mode.
The operation of the driver’s cab and the hopper vibrator both use Siemens M440 series frequency converters. The motors of other auxiliary mechanisms are directly started. The overall control system of the machines uses Siemens S7300 series PLC with a modular structure. A main station is set in the electrical room and a slave station in the driver’s cab, and the Profibus – DP communication control method is used between the main station and the slave station.
A 10 – inch color touch screen GP2500S is installed near the control console to monitor the overall machine’s operating status and display faults. The control system can achieve functions such as automatic grab operation, automatic and semi – automatic luffing unloading. It communicates with the host computer via the PLC Ethernet module and an 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, enabling real – time fault monitoring. Meanwhile, it records historical faults and provides information to guide fault – solving.