温度对电涡流位移传感器测试误差影响分析

Analysis on impact of temperature on test errors of eddy current displacement sensor

针对常用的恒频调幅式电涡流位移传感器,重点讨论了传感器探头和被测导体因温度变化导致测试结果的系统性偏移规律,并通过室内试验进一步论证了温度的影响。分析表明:1)温度变化引起传感器探头测试结果偏移,二者呈负相关变化趋势; 2)被测导体存在临界等效电阻R*,当等效电阻R2≥R*,温度与输出结果间呈正相关变化规律,反之则呈负相关变化; 3)试验测试结果受温度影响呈明显正漂移,且在小范围温度波动下输出值漂移也出现较好的跟随性,在测试精度要求高的情况下应予以修正。

Aiming at common constant-frequency amplitude modulation eddy current displacement sensor,systematic deviation rule of the test results which are caused by the temperature changes of the sensor probe and the measured conductor is discussed.And the influence of the temperature is validated by the laboratory experiment.The analysis shows that:(1)Due to the temperature deviation of the sensor probe,the test result is shifted,and the deviation result of the sensor probe has the negative correlation with the tempature changes;(2)the tested conductor has a critical equivalent resistance R*,when the equivalent resistance R2≥R*,temperature changes and output results are positively correlated with each other,otherwise it is negatively correlated;(3)The test result has the obvious positive drift phenomenon affected by the temperature changes,The output value drift also appears better follow-up within a limited extend of temperature fluctuations.In consideration of high test precision requirements,it should be amended.