Research And Design Of Multi-channel High Precision Temperature Measurement Device

As an important environmental parameter in the development and test of aircraft,temperature plays an important role in guiding the design and improvement of aircraft.Due to the complex internal environment of the aircraft,the wide temperature range,and the existence of multiple electromagnetic interferences,higher requirements are placed on the acquisition accuracy,channel number and reliability of the temperature acquisition equipment.In order to meet the requirements of the internal environment temperature acquisition and testing of the aircraft,a multi-channel high-precision temperature measurement system is analyzed and designed.The system mainly collects,transforms and encodes the temperature signal,and converts the temperature signal into an analog voltage signal through the thermocouple sensor.Then,the analog signal is converted into a digital signal by an analog-to-digital converter,and transmitted to the upper computer test bench for real-time temperature display and data processing.The multi-channel high-precision temperature measurement system is mainly composed of a thermocouple sensor,a temperature acquisition and forwarding device,a temperature acquisition and conversion device,and a host computer test bench.In order to improve the acquisition accuracy and anti-interference ability of the system,the research and optimization design are carried out from two aspects of hardware circuit and software logic.In the aspect of hardware circuit,K-type thermocouple sensor is designed and used,and K-type thermocouple compensation is applied.The circuit performs temperature compensation processing on the thermocouple temperature signal to improve the adaptability of the device to the ambient temperature,thereby improving the acquisition accuracy.In order to improve the anti-interference ability of the system,the signal conditioning circuit,the second-order voltage-controlled filter circuit and the anti-aliasing filter circuit are designed to improve the signal-to-noise ratio and ensure the signal transmission is stable and reliable.In terms of logic design,FPGA is used as the main controller,control signal acquisition,channel switching and data transmission,which greatly improves the data processing capability.The calibrationmethod of the K-type thermocouple is improved,the linearity error is reduced,and the acquisition accuracy and accuracy are further improved.At the same time,dual-port RAM cache logic is also adopted,which greatly improves the data transmission efficiency and ensures the integrity and continuity of data transmission.And the CAN bus communication protocol is used to ensure the stable and reliable data transmission of the two measuring devices,and has a CAN reserved interface,which is convenient for increasing the collecting device and changing the number of collecting channels,so that the collecting system has higher flexibility and inheritability.Finally,the system performance indicators and functions are verified.Through a large number of high temperature,low temperature,vibration and acceleration tests,the temperature acquisition system has high precision and high reliability,meets the requirements of mission indicators,real-time monitoring and analysis of the internal ambient temperature of the aircraft.