便携式液位测量仪的研制

Studying and Making A Portable Meter to Measure the Liquid-Level

便携式液位测量仪以集成锁相环路解码器LM567作为超声波检测元件,以89C2051单片机作为主控元件,可用干电池供电。介绍了超声波液位测量的原理、电路及测控程序。用超声波测量液位具有非接触、可测量低温介质、无可动部件长寿命等优点;以LM567作为超声波检测元件降低了系统的价格,提高超声波捕捉能力;采用单片机来控制超声波的发射与接收,并且经温度补偿后计算出液位,使检测具有更高的智能性。对由于超声波声速变化及LM567输出延时引起测量误差的原因作了详细的分析,并提出了提高调整波速精度及调整输出延时的措施。

The portable meter to measure the liquid-level uses the phase-locking IC LM567 as the detecting device ,MCU 89C2051 as the main control device, battery to provide the energy. The theory ,the circuit, and the program is introduced. The advantages of keeping clear of the medium which is detected, being likely to detect low temperature medium, no movable component, longevity and so on can be obtained when using the ultrasonic to detect the liquid-level. The system＇s price can be reduced and the ability to catch the ultrasonic can be improved with LM567 as the detecting component of the ultrasonic. The more intelligent can be obtained when using the MCU to control the emission and receiving and to calculate the liquid-level after temperature compensating. The causes by the ultrasonic velocity＇s variety and the delay of the LM567＇s output to bring the measuring errors is analyzed and the method to reduce it is by heightening the precision when adjusting the ultrasonic velocity and the delay is also put forward.