Research On Application Of Fiber Dual-ring Network In Floating Dock Lifting Control System

Floating dock in the modern shipbuilding industry is used more and more extensive. And the LCS (Lifting Control System) is an important indicator of the degree of automation for the floating dock, so take the fuzzy control technology in LCS is important for efficiency improving. At the same time, take the fiber network and the redundant network in LDS is also important for the stability improving.This LDS is designed for the floating dock which is building in Tianjin. The control core of the project is S7-400H PLC which is product by Siemens. And the three layers industry networks are used for the communication. For the software function, the UCDS have three control modes, which is automatic control at CCR (Central Control Room) mode, manual control at CCR mode and manual control at PM (Pump Room) mode. The automatic control at CCR is the main control mode. By making the floating dock test water cycle experiment, float upward, drive down automatically, it can strongly reduce the operator's work intensity.This project adds redundant design in both hardware and software. In hardware, it improves the stability by taking the fiber dual-ring network into the system. At the same time, it make the key components can be checked, changed or repaired on line by hot-redundancy designation. In software, the system program adds the redundant function blocks which as the complement to the hardware redundancy.This system is simulated in our school's PLC Lab. All parameters, especially in stability, meet the design requirements which were set by the ship-owner. At the same time, this system can be easily transplanted to other floating docks. So this system has an important role in proving the development of lifting control system.