用于模拟铂电阻温度传感器的可编程精密合成电阻

摘要

在舰船动力装置控制系统中,温度测量设备通常采用铂电阻温度传感器对大量的温度信号进行采集,并将温度信号转换成电阻信号.当这些温度测量设备进行调试、试验时,需要使用电阻器模拟铂电阻温度传感器给出所需的电阻信号.介绍了新型的可编程精密合成电阻以替代传统的电阻箱,该合成电阻采用运算放大器和D/A转换器等器件构成单口网络,通过编程控制输入电压和输入电流的比值获得期望的电阻值.详细分析了该电路误差产生的原因,给出了以ICL7560和AD5543为核心的具体实现电路,其输出电阻误差可控制在0.02Ω以内,对应温度信号在0.05°C以内.该合成电阻具有体积小、精度高、可编程数控的优点,是温度测量设备试验时所需的重要设备.%In ship power plant control system, platinum resistance temperature sensors are used to collect a large number of temperature signals and convert them into resistance signals. During debugging and test of these devices, resistor is used to simulate platinum resistance temperature sensor to give the required resistance signal. We introduced a new programmable precision synthetic resistance as substitute for the traditional resistance box. The synthetic resistance used operational amplifiers and D/A converter to constitute one port network, controlled by programming the ratio of input voltage and input current, so as to achieve the desired resistance value. This paper gives a detailed analysis of causes of error in the circuit, and presents a specific circuit with ICL7560 and AD5543 as the core device, and maintains output resistance errors within 0.02 ft and corresponding temperature signals below 0.05℃. The synthetic resistance has the advantages of small size, high precision and programmable feature, and that is the important device required for the test of temperature measurement sensor.