The Study Of Wide Range Temperature Signal Remote Measurement Technique

The launch tower must withstand high temperatures up to thousands of degrees while therocket lunching, which caused the damage on the launch tower. It is likely to become unstablestate of launch tower after repeated rocket task.This will bring uncertainty for rocketslaunching, which maybe led to the failure of the task.It is necessary to monitor thetemperature environmental effects caused by the rocket launch. The temperature signal canprovide the basis data for the health assessment and life prediction of launch tower. In thisarticle, based on the characteristics of the environmental effects of rocket lunching, design atemperature tester.On the basis of in-depth research on the background of the demand, we design a testerfor detective the environmental effects of temperature when the rocket is launched.Temperature tester including three parts: thermocouples, transmitters, memory acquisition.Using the thermocouple temperature sensor as a front end.Thermocouple for temperaturechanges induced emission, change the temperature signal into a voltage signal;Achieve thehardware circuit of transmitter in order to amplify and turn the output voltage signal of thethermocouple into a4mA~20mA current signal for the memory acquisition,so that the testerovercome the interference of signals come from the complex environment;memoryacquisition is designed four modules, each acquisition and storage module has16channels ofacquisition, a total of64acquisition channels, to ensure measuring points can be distributed inall directions of the tower floors.Each memory acquisition module make by thecurrent-to-voltage module,anti-aliasing filter,analog to digital conversion module,FPGAcontrol module,FLASH module.It adopted50meters long cable connection between thetransmitter and the memory acquisition;transmitter include the thermocouple cold-junctioncompensation and amplification circuitry, and0V~5V turn to4mA~20mA current circuit.Since the rocket launching process through a very short period of time but temperature ofsome parts of the tower rose to nearly a thousand degrees, so we use the sample rate of5times of the temperature signal frequence;the use of FPGA parallelism characteristic control of multi-chip simultaneous sampling ADC;uses polynomial fitting and linear output signal forthe thermocouple linearization,the measurement accuracy is improved.Finally we give thetester a preliminary test.Through testing, the measurement accuracy of the design reaches±5℃, achieve thedesign requirements. The design of the transmitter and the acquisition and storage circuit hasachieved the demand for the ambient temperature detection while space rockets launching.