Development Of Intelligent Ultrasonic Liquid Level Sensor

Along with the development of science and technology, mature ultrasonic technology can be found in many fields. This kind of level sensors is non-contact equipment mainly used for the chemical raw material liquid level measurement .The ultrasonic measurement method has many advantages compared with others which have widely used for many years. To satisfy the requirement of inflammable chemical material non-contact liquid level measurement, intelligent sensor scheme is proposed in this paper.The drawback of conventional sensor with single function is overcomed.This intelligent sensor posseses many outstanding performances: automatic measurement, data processing, various forms of output and data communications.The intelligent sensor is designed to achieve precise measurement and communicate with hose computer and other equitments in three ways. The intelligent sensor is developed of hardware circuits and sortware. Hardware circuits include the circuit of level information collection, control unit, user interface circuits of communication with outside. In circuit, the 16-bite consumption microprosessor, MSP430F449 is chosed as the hard core of the electrical board.The processor is powerful in computing, possesses bigger storage space up to 60KB and is rich in peripherial modules.This makes it easier to develop electrical circuit with more complicated functions.Commonly used ultrasonic probe is adopted as sensing component., the circuit for temperature compensation is carefully designed in order to achieve precise measurement. Based on circuits, the paper selects C laugange to program. The routine is made of liquid level measurement procedure, human-computerinteraction procedure, RS-232 serial communication procedure, Ethernet data transmission procedure and 4~20mA two-wire current transmitte procedure. In this paper, modular software is easy to program, revise and expand.The result of experiment has showed that the intelligent sensor has the ability of precise measurement and communication with outside in three ways through the select of keys.