Data Acquisition Of Thermal Flow Field In Electro-optical Pod System Design

The data acquisition system of thermal flow field in the electro-optical pod was used to collect the temperature and pressure signals inside the electro-optical pod,and send the collected data to the computer,it was of great significance to guide the overall design,cooling form and later product improvement of the electro-optical pod.The diversity of the working environment and the high integration of the components in the pod has put forward strict requirements on how to achieve high-precision data acquisition.In order to meet the design requirements,according to the idea of modularization,a set of low-noise,high-precision multi-channel data acquisition system was designed.First of all,the design requirements were analyzed,the sensors selection was completed,and the layout of the sensors in the pod was studied and analyzed;the multi-channel signal acquisition mode was a combination of serial and parallel acquisition mode,the whole design scheme of data acquisition system was put forward.Secondly,in the sampling circuit design of thermocouple signal conditioning,the cold side of thermocouple was compensated by the cold side compensation circuit design,and the low noise and high precision reference voltage circuit design was adopted to reduce the power noise interference;the signal of thermocouple was filtered twice to reduce the interference and noise in the circuit;in the design of pressure sensor signal conditioning sampling circuit,the pressure sensor signal filter circuit was also designed to reduce noise interference,through amplifier circuit design and ADC driver circuit design,high precision acquisition of pressure sensor signal.Then,the control logic design of the data acquisition system was completed.The control logic design of ADC was realized by using SPI communication protocol.The multi-channel data acquisition was realized by using analog switch control logic design;and the interference noise was further filtered by using FIR digital filter design;the sampling data was processed by adding ID frames,and the data was distinguished on the computer;the data was transmitted at high speed through the logic design of ethernet data transmission module.Finally,a calibration experiment platform was built to verify the integrity of data transmission of the data acquisition system;and the calibration and error analysis of the pressure acquisition system and the temperature acquisition system are completed,the results showed that the accuracy of the pressure acquisition system was ±0.326% F.S,the accuracy of temperature acquisition system reached ±0.169% F.S,the overall accuracy of the data acquisition system met the design requirements;a test platform for the data acquisition system of the thermal flow field in the electro-optical pod was built;the data acquisition system was used to successfully realize the data acquisition of the thermal flow field in the pod,and after data analysis,the results showed that the performance of the system was stable and reliable,and the correctness of the design was verified.