基于ARM的实验室数字源表设计

Design of laboratory source meter based on ARM

设计了一种以ARM Cortex-M4为核心的数字源表。通过数模转换芯片AD5422实现电压、电流源输出,输出精度在0~10 V,0~20 mA范围内达到五位,误差在0.02%以内;通过模数转换芯片LTC2440实现对电压、电流、电阻的测量功能,测量精度达到六位半,其中电压测量误差小于0.003%;信号的测量经选通放大后由ADC进行采样,采用滑动均值滤波滤除采样干扰,最小二乘法校准采样数据;测量和输出数据在LCD上显示。本数字源表成本低,集成度高且方便操作,适合在电子信息类本科教学实验中广泛使用。

A source meter has been designed,which is based on ARM Cortex-M4.The output of voltage and current source is implemented by the AD5422,and the output accuracy is 5 digits in the range of 0~10 V and 0~20 mA,the error is within 0.02%.The measurement functions of voltage,current,and resistance are realized by LTC2440,and the measurement accuracy reaches six and a half digits,the voltage measurement error is less than 0.003%.The measurement of the signal is sampled by ADC,which is amplified by strobe,the sliding mean filter method has been used to filter the sampling disturbance,and the least square method is used to calibrate the data.The measurement and output data are displayed on the LCD.The digital source meter has low cost,high digital integration and easy operation,which is suitable for being widely used in the undergraduate teaching experiment of electronic information.