电流采集程序,将模拟电流信号转换为数字信号,供上位机使用.-Current acquisition process, the analog current signal is converted to digital signals for the host machine.

西门子双极性换算关系 4-12-20mA，假设电流电压比800/5,6300/100， 采样原值X,实际工程值Y，注意：12MA工程值理论是为0，可适当减零漂(SIEMENS bipolar conversion between 4-12-20mA, assuming the current voltage ratio 800/56300/100, sampling value X, value engineering Y, attention: 12MA value engineering t