Design Of Liquid Level Detection System For High Viscosity Crude Oil

Liquid level detection technology is widely used in food,medicine,petrochemical and other fields.In the petrochemical field,it is necessary to track the height change of liquid level in the crude oil tank in real time for precise industrial control.In the traditional crude oil tank level measurement,the steel belt float level gauge and capacitance level gauge are mainly used,which have low measurement accuracy and can not meet the industrial demand;for the large crude oil tank level measurement,the manual detection method is also needed,the measurement accuracy is not enough and the operator’s personal safety is difficult to guarantee.Therefore,it is of great significance to design a liquid level detection system for crude oil tank to improve the measurement accuracy and production efficiency.After studying the development of oil level detection technology at home and abroad,this paper designs a set of oil tank level detection system based on laser ranging.In the actual field experiment,after confirming the feasibility of laser measurement for crude oil tank,the phase laser displacement sensor is selected as the liquid level measurement sensor.According to the requirements of the project party,the remote signal transmission is applicable to 4～20m A and Modbus communication modes.In the industrial field,the commissioning and measurement results are displayed in real time through LCD screen and infrared remote control input field equipment.Stm32f103RCT6 single chip microcomputer is selected as the microprocessor.On the basis of designing the minimum system of this single chip microcomputer,hardware circuits such as power supply stabilization,V / I conversion,LCD display,etc.are designed,and PCB circuits are drawn and printed.On the basis of hardware design,software programming is carried out to achieve the complete system functions.After the completion of hardware design and software programming of the system,the function test is carried out for the system,which mainly verifies the functional integrity of each module of the system,the normal display of LCD,the control function of infrared remote control for the system,and the normal output of4～20m A and MODBUS signals.Among them,digital to analog conversion and V / I conversion are used in the 4～20m A communication mode,so the measurement accuracy is analyzed.The experiment shows that the absolute error of the 4～20m A signal output system is less than 1.5cm within the range of 50 m,which meets the demand of crude oil tank level detection.