System and method for detecting tension and length of cable of winch of marine towing machine

The invention relates to a system and a method for detecting the tension and the length of a cable of a winch of a marine towing machine, particularly applicable to tension detections of a mooring line of the marine towing machine of an offshore drilling platform, and length measurements as well as velocity measurements when taking up and paying off the mooring line. The detection system provided in the invention comprises a load sensor, a coder, a PLC electrical module and a touch screen display module. The detection method comprises the following steps: the coder acquires and transfers position and velocity data signals of the cable, the load sensor acquires and transfers load data signals, the PLC calculates the length and the velocity when paying off the cable, the PLC calculates the tension of the cable, and performing result showing, parameter setting and ultralimit alarming. The detection system and detection method provided in the invention have the following advantages: the length data information, the velocity data information and the tension data information when taking up or paying off the cable can be obtained timely and accurately to guarantee the security and stability of the offshore work platform; detection situations can be displayed on the touch screen, and the parameter setting as well as the ultralimit alarming of the length and the tension of the cable can also be realized by the touch screen display module; and safe operation of the winch and the cable of the marine towing machine can be protected effectively.