电子分析天平的非线性影响与补偿方法研究

Nonlinear effect of electronic analytical balance and its compensation

基于电磁力平衡传感器的电子分析天平非线性影响复杂,现有天平的非线性补偿主要依靠硬件电路实现,调试烦琐,示值误差大,一致性差。分析了电磁力平衡传感器的动圈位置、工作电流、环境温度、永磁体性能等非线性影响机理,提出了电磁力平衡传感器机械平衡优化与空间限位、取样电阻与传感器匹配、传感器多点温度测量等硬件优化方法,建立了电子分析天平非线性影响的牛顿插值补偿算法,实现了电子分析天平的非线性自动补偿。检验结果表明,采用研究的补偿方法对量程210g、分辨力0.1 mg的电子分析天平补偿后,全量程示值误差≤±0.3 mg,优于国家标准《JJG 1036—2008电子天平检定规程》规定的一级天平示值误差指标。

The nonlinear effect of electronic analytical balance with electromagnetic force balance sensor is complex;and in current balance,the nonlinear effect is compensated mainly using hardware circuits,which is fussy and the results are inconsistent.In this paper,the nonlinear mechanism of electromagnetic force balance sensor is analyzed,which includes the sensor movable coil position,working current,temperature and permanent magnet performance.Many hardware optimal methods are proposed,which include optimizing the mechanical balance,space limit,matching sampling resistor with sensor and measuring multi-point temperatures of the sensor.Moreover,a nonlinear compensation method based on Newton interpolation is proposed.This proposed method was used on an electronic analytical balance with a range of 210 g and resolution of 0.1 mg;and test results show that the indication error is not greater than 0.3 mg,which is less than the indication error for the 1st class balance specified by Chinese National Standard,＂JJG 1036—2008 Verification Regulation for Electronic Balance＂.