PT100温度测量电路.docVIP

The Resistive Temperature Detector (RTD) 电阻温度检测器（RTD） In addition to thermocouples for measuring temperature, instrumentation engineers frequently use Resistive Temperature Detectors or RTDs. 除了 ??用于测量温度的热电偶，仪器仪表工程师经常使用电阻温度检测器或RTD。 These are devices whose DC resistance varies (almost) linearly as a function of temperature. 这些设备的直流电阻变化（几乎）作为线性温度的函数。 Perhaps the most common of these is the PT100, a platinum based sensor whose resistance at 0oC is exactly 100 Ohms, (see Table 1). 或许其中最常见的是PT100，铂为基础的传感器，其电阻在0℃，正是100欧姆，（见表1）。 As the sensors temperature increases so does its resistance, in a reasonably linear manner. 由于传感器的温度升高其电阻也是如此，在一个合理的线性方式。 Table 1 shows the variation in resistance of a PT100 sensor with temperature. 表1显示了一个PT100传感器的电阻随温度的变化。 While the temperature coefficient varies slightly over a wide range of temperatures, (typically 0.0036 to 0.0042 Ohms/oC), it can be considered reasonably constant over a 50 or 100 oC range. 而温度系数略有不同在一个很宽的温度范围内，（通常为0.0036至0.0042欧姆/ o C），它可以被认为是合理恒定在50或100 o C范围内。 The commonly accepted average temperature coefficient is 0.00385 Ohms per oC. 普遍接受的平均温度系数为0.00385欧姆每o C。 Accordingly the PT100 can often be used without linearization over such a range provided the appropriate coefficient is evaluated. 据此，PT100往往可以在不超过这个范围线性化使用提供相应的系数进行评估。 This device is also capable of withstanding a wide range of temperatures, from -200 to 800oC, and for some applications the variations in temperature coefficient can be tolerated. 这个装置也能承受的温度范围很广，从-200到800 o C的能力，以及一些应用中的温度系数的变化可以容忍的。 Further, the PT100 provides stable and reproducible temperature characteristics. 此外，PT100提供了稳定和可重复的温度特性。 For a given base resistance R o , the resistance of an RTD at T oC is given by: 对于给定的基极电阻R O，一个RTD电阻在T o C为： Or 或 … (1) ... ...（1） Where R o is the base resistance corresponding to T o , (100Ohms at 0 oC) and 其中R O是基极电阻对应到T O，（在0 o C 100欧姆）和 is the temperature coefficient, (0.00385Ohms per oC). 是温度系数（每o C 0.00385Ohms）。 Thus R(100 oC ) = 138.5 Ohms . 因此，R（100