同基准16路电流型测温电路设计与应用

A Design and Application of 16-way Current-type Temperature Measuring Circuit with the Same Reference

在许多实际的应用系统中,需要同时测量多点温度,为了解决多支路测温需要相同参考标准的问题,保证各路参数具有可比性;巧妙地设计同基准A/D转换电路,运用低导通电阻模拟开关构建矩阵开关进行分时切换各支路,有效地解决了多支路同基准测量问题;结合实际应用确定A/D转换器输入电路滤波电容大小与开关切换延时的关系;利用台阶电阻使A/D转换器的输入端的"零"电平得到抬升,偏离A/D转换器非线性段,解决了微小信号输入的测量精度;对于温度测量普遍使用的铂电阻传感器,利用模拟开关实现了铂电阻传感器静态下预热电流与测量状态下工作电流的电路转换,保证电路的信号稳定起到很好作用;在实际的应用系统中,检定数据和使用效果表明,同基准16路电流型测温电路具有高稳定度、高精度特点,适用于各种相参测量系统中使用。

In many practical applications,it is necessary to measure the temperature at the samethe same reference standard for multi branch temperature measurement,and ensure thatthe parameters are comparaberence A/D conversion circuit,the use of low resistance analog switch matrix switch of each branch switch construction points, effectivelysolve the multi branch with reference measurement problems; combined with the practical application to determine the relationship between the A/D converter input circuit filter capacitance and switching delay; using step resistor A/D converter input the ＂ zero＂ level is uplifted, deviate from the A/D converter to solve the nonlinear range measurement precision of small signal rnput; platinum resistance sensor for tem-perature measurement rn common use,the circuit current platinum resistance sensor static and preheating current measurement of the conver-sion of analog switch,ensure stable signal circuits play a very good effect. In the actual application system,show that effect of using the same reference,16 current type temperature measuring circuit has the characteristics of high stability,high precision, ap-plicable to all kinds of coherent measurement system using.