The Research Of Shiplift Monitoring System

The shiplift is the one of the most important means to realize navigation through the high dam, and it is also the main working platform for the new ship-building and ship-fixing in the dock in the shipyard. It is a system engineering which covers many fields including hydrodynamics, electric controlling and mechanism etc. Its running working circumstance is more complex which needs much high reliability and stability.In this research according to the present condition and its technique request of shiplift platform currently in our country, we design a set of monitoring system. The shiplift platform is composed of longitudinal lissome coupling three platform, having 70 meters length, 13 meters width, which has a total lifting ability of 1100 tons. It is rised and lowered depending on 14 sets of winding engines synchronous operation.This monitoring system consists of industrial control upper-computer having the friendly human and man interface, advanced reliable PLC lower-processor, 14 converters as the driving unit, we distinguishingly choose SIEMENS industrial computer, SIEMENS S7-300 series PLC and SIEMENS 6SE70 series (Vector Control) converter. The application of PROFIB US-DP fieldbus technology that is transferring speed fast, opening finely and international general use to relalize the communication between upper-computer and PLC, PLC and 14 converters. The fiber optic cables of SIMOLINK are used to communication among converters. PLC writes to converters the control words and rotational speed set value, at the same time read the status words and the real values of the rotational speed from the converters. Converter acquisitiones motor's rotational speed via the optic-electric encoder, then form the closed-loop speed control. It can complete the quickly delivering data among converters through specific protocol SIMOLINK, and guarante the converters working synchronously at one common rhythm, finally to ralize the request of many points at the same speed.The monitoring system has been debugged and used in the shipyards in Dalian. It is running safely and reliably and easy to be operated.