基于对数的NTC热敏电阻测温系统的设计

摘要

针对NTC热敏电阻阻值与温度(R-T)的非线性特性,为了提高测温精度,提出一种三阶对数公式法对R-T特性进行分段曲线拟合.该测温系统以三阶对数公式为基础进行了软硬件设计,实现了对船用柴油机的机油温度、冷却水温度的高精度测量.通过实验测试表明,在0～120℃温度范围内,采用该测温系统的测温误差小于±0.3℃.该测温系统已应用于某公司的船用柴油机状态监控仪表,进行了装船测试,测温效果良好,通过了某船厂的验收并已交付,运行正常.%Since the NTC thermistor's resistance and temperature(R-T) there is a serious non-linear characteristics, in order to improve the temperature measurement accuracy,design idea about the third-order natural logarithm formula method was put forward which was used for piecewise curve-fitting of R-T's characteristics.The temperature measurement system's hardware and software design is based on the third-order natural logarithm formula method,which realizes high-precision measurements for oil temperature and cooling water temperature of the marine diesel. Experimental tests show that the temperature in the range of 0～120℃, the temperature measurement system using the measurement error is less than ±0.3℃. the temperature measurement system has been applied to condition monitoring instruments for marine diesel of some company,it has been tested on board,temperature measurement effect was excellent,it has been accepted and delivered by a certain shipyard, it is operating normally.