Research On Cable Eccentric Wall Thickness Measuring Instrument Based On Production Line

The detection of eccentric wall thickness of cable is the most important part in the production process of wire and cable.The deviation of cable core will affect the service life and transmission efficiency of cable products.If the insulation layer is smaller than the specified range,the probability of cable damage will be increased and the risk of fire will be increased.The traditional contact measurement method is not only inefficient,need to destroy the cable,and can not find the problem in time,resulting in a large amount of waste of raw materials.Therefore,it is of great significance for cable industry to introduce on-line detection technology.Aiming at this actual problem,this paper develops an on-line detection device for cable eccentric wall thickness based on eddy current and laser diffraction.First of all,through consulting a large number of data,master the current domestic and foreign cable detection devices used technology and existing problems,summed up the advantages and disadvantages of several common measurement methods.On this basis,the principle and application method of eddy current sensor and CCD sensor are introduced in detail,and the overall research and development scheme of cable eccentric wall thickness measuring instrument is presented.Then this paper is divided into three parts to design the measuring system: sensor,upper computer and lower computer.In the design of sensor,in order to improve the precision of CCD sensor in the principle of laser diffraction,the circuit is treated with binarization.The hardware circuit of amplifying,filtering and rectifying the output signal of eddy current sensor is improved by using the OPA690 amplifier,and the error in the signal is reduced.With STM32F7 chip as the core,TLC5540 is selected according to the system requirements to realize analog-to-digital conversion,AD9833 pulse generator,ADM2486 transceiver,power management module,etc.,which can realize various design functions of peripheral circuits.Linear CCD adopts a high-precision sensor TCD1702 C containing 7500 photosensitive elements.With PC as the core,the upper computer has completed the page design,designed a convenient human-computer interaction interface,which can realize the control of the upper computer to the lower computer,as well as the analysis and processing of data.Finally,the accuracy and repeatability of the system are tested.Through the analysis of the test results,it can be seen that the cable eccentric wall thickness measurement system can be measured within the range of 1-41 mm,with the error range ≤±5μm.The error sources include the error caused by the light source and the error caused by the linear CCD image collector.Through the analysis of the test error of the system,this paper finally summarizes the measurement system and points out the problems that may occur in the system.It also gives solutions to these problems and prospects its application prospects.