基于电容式传感器的建筑物围护结构含水率测试

设计的平面电容式传感器可感应围护结构中水分的变化,给出了传感器的工作原理,针对小电容检测的抗干扰问题,采用了加保护电极和利用驱动电缆传输信号的技术,结合改进的充放电微电容检测电路,对传感器的测试深度和灵敏度与极板尺寸的关系进行了研究和优化。设计了基于嵌入式微控制器的含水率测试系统,实验结果表明:该系统可以用于一定深度的围护结构的含水率现场测试。

Moisture test of building envelope based on capacitive sensor

The planar capacitance sensor is specially designed for the process of the test which can induce the changes of the water in the building envelope.The working principle of the sensor is given.In order to solve the interference problem of small capacitance in dectection,a sensor with protection electrode and the singal transmission technology of actuation electric cable are used.With the improved micro-capacitance measurement circuit based on charging/discharging principle,the optimization is given to the relations of test depth and sensitivity of the sensor.The system of moisture test in the building envelope is based on embedded microprocessor unit.The experimental results show that the system can be used for moisture test of the building envelope in a certain depth at the scene.