两线制电容式数字液位传感器研制  

Research and Design of Two-wire Capacitive Liquid-position Sensor

作　　者：孙万里[1] 刘宪林[1] 

机构地区：[1]郑州大学电气工程学院,河南郑州450001

出　　处：《仪表技术与传感器》2009年第3期12-14,共3页Instrument Technique and Sensor

摘　　要：电容传感器在液位测量领域应用广泛，但在实际应用中，常会因被测介质和测量范围的不同需要现场校准传感器。为简化校准方法，设计了以PIC16F684单片机为核心的数字液住传感器。该传感器采用模拟校准和数字校准2种方式。出厂前进行模拟校准，以确定量程。现场安装时进行数字校准，通过对2个有较大差值的不同液位的实测，对传感器的零点和放大倍数进行修正，以确保液位传感器的精度。传感器采用AIM21构成两线制4～20mA电流信号输出，方便与现有仪表或微机系统等配合使用。Capacitance sensor is widely used in liquid-position measurement, and calibration of sensors on-site is necessary in practical application, for the changes of mediums and measurement range. To simplify the calibration method, this paper designed a digital liquid-position sensor, it used the PICI6F683 MCU as the core. The sensor adopted two methods in calibration, analog method and digital method. Analog calibration was taken to make sure the range of measurement before leaving the factory. Digital calibration was used when the sensor was to be installed on-site. The actual measurements of two liquid-position values with differ- ences between them, were taken to correct the zero point and the times of magnification, and the precision of the liquid-position sensors was ensured. The structure of two-wire output of 4 mA to 20 mA electric current by using the AD421 MCU is convenient to coordinate with currently existing instruments or microcomputer system.

关 键 词：液位传感器 传感器校准 两线制 AD421 

分 类 号：TH8[机械工程—仪器科学与技术]