量程计算器 把4-20ma信号对应成任何量程的计算器-Range calculator to 4-20ma signal corresponding to the calculator into any range

51单片机接入差分信号重量传感器，设定额重，输出控制，同时DA转换（AD421芯片）输出4-20mA。-51 single access differential signal of the weight sensor, set the amount of weight, output control, while the DA converter (AD421 chip) output 4-20mA.