热强度试验中热电偶调理模块的设计与应用

Thermocouple Conditioner Module Design and Application in the Thermal Strength Test

热强度试验现场环境复杂,会对热电偶、热流等微弱电压信号产生较大电磁干扰,影响系统测量精度;因此,需要设计一款热电偶调理模块,对小信号进行隔离放大并抑制环境干扰,有效还原真实信号,提高系统的测量精度;首先,信号通过差分滤波电路,滤除噪声后进入高分辨率ADC,转换为数字信号;然后通过CPU进行信号处理,得到对应的温度值,再根据按满量程线性化计算,将输出编码发送到DAC,按预先设置好的信号输出到数据采集仪器;通过实测证明,热强度试验中的热电偶、热流以及其它微弱信号,均可通过此热电偶调理模块调理成大电压或电流信号然后输出,可以有效的抑制干扰,确保热强度试验中系统的测量精度。

Since the thermal strength test environment is complex, there is strong electromagnetic interference in measuring low voltage signals, such as thermocouples and heat flux, thus affect system measurement accuracy. Therefore one thermocouple conditioning module is designed, aiming at isolating and amplifying the low voltage signals as well as jamming interference, recovering signals effectively, then im- proving the accuracy of the system. At first, real signals go into differential filter circuitry with noise filtered, then are converted into digital signals by passing through high resolution ADC. And then are processed by CPU, we get corresponding temperature values. Finally, do line- ar calculation in full scale, send output code to DAC, then output signal to DAQ instrument. It was proven by test, all low signals including thermocouples, heat flux and other low voltage signal in thermal strength test, can be converted to high voltage or current signals by using thermocouple conditioning module, thus reduce the interference effectively and ensure the system test accuracy can be achieved.