Research On Key Technologies Of Ultrasonic Liquid Level Detection System Based On ARM

The ultrasonic liquid level detection technology, for its advantage that canrealize non-contact liquid level measurement, is widely used in industrial field ofpetroleum, metallurgy, chemical industry etc. It has also been widely used in waterlevel of rivers, sewage treatment and other environmental monitoring areas. With thedevelopment of microelectronic technique, sensor technique and other newtechnology, ultrasonic liquid level meter being developed towards delete of intelligentand integration, more adaptable the new requirements in the field of liquid levelmeasurement. According to the analysis and summary of current situation anddevelopment trend of ultrasonic liquid level meter, and new requirement onmeasurement environment, this thesis designed a kind of ultrasonic liquid leveldetection system which based on embedded microprocessor S3C6410and Linuxoperating system.This thesis analyzes the current situation of ultrasonic liquid level meter and itstrend of development, elaborated the important significance of the high performanceliquid level meter to liquid level measurement. Through the analysis of thecharacteristic of ultrasonic, ultrasonic liquid level detection system is determinedusing frequency of ultrasonic with40KHz; comparing the different methods of liquidlevel measurement, this thesis choses pulse echo method (time difference method) torealize the liquid level measurement of ultrasonic liquid level detection system.This thesis takes the embedded microprocessor and the embedded open-sourceoperating system as the core, researched the key technology on the realization ofembedded ultrasonic liquid level detection system, proposed a hardware and softwarearchitecture which consist of Samsung S3C6410microprocessor and embeddedLinux operating system.This thesis takes the S3C6410microprocessor as the operation and control coreof liquid level detection system, designed the following hardware module: theintegrated ultrasonic transceiver module, simplified the transmitting and receiving ofthe ultrasonic wave; the sampling circuit, to realize the ultrasonic echo signal’s acquisition and A/D conversion; the serial communication module; the CAN businterface; the temperature detection module and power management module.The software architecture design mainly completed the transplantation of Linuxoperating system; using the wavelet transform algorithm to design an echo signalprocessing program, identified the ultrasonic transit time by software; designedtemperature compensation program to compensate for the speed of ultrasonic andimproved the measuring precision of ultrasonic liquid level detection; designed serialcommunication program and CAN communication program, improved thecommunication ability of the ultrasonic liquid level detection system.