一、前言在国民经济各部门中,在很多场合下须要测量液位,尤其是水位。古老的测量方法是:用水尺和水位测针。但它们不能给出电信号,无法进行远传、控制和数据处理。由于电子技术的高速发展,因此现代采用电子技术的各种型式的液位计种类不少。但综观国家产品样本所列各种液位计,其精度最高的包括数字式的在内,也只是毫米级。作为一般用途是可以的,但在科研试验中,例如水力模型试验(水工、河工、港工、水力机械模型等)中,由于原型的绝对误差将随模型的测量误差而作数十倍数百倍的放大,毫 I. Preface In all sectors of the national economy, on many occasions it is necessary to measure the liquid level, especially the water level. Ancient methods of measurement are: water gauge and water level stylus. However, they can not give out electrical signals and can not conduct remote communications, control and data processing. Due to the rapid development of electronic technology, there are many types of liquid level gauges in modern electronic technology. However, a comprehensive survey of national product samples listed in various levels, including the highest accuracy, including digital, it is only millimeter. However, in scientific experiments, such as hydraulic model tests (hydraulic engineering, river engineering, port engineering, hydraulic machinery modeling, etc.), the absolute error of the prototype will be several hundred times as many times as the measurement error of the model Magnification, milli