本程序采用MSP430F149低功耗芯片，由键盘按键输入所需控制的电流源的值输出，电流源范围4~20mA，通过功能转换算法，输出可在百分比、数值之间任意切换，具备阶梯控制输出，输出可在五点任意设定，单按键电源控制更适合电池供电使用。(This program uses low power MSP430F149 chip, the current source control required by the keyboard input value of the output current range of 4~20mA source, through the function conversion algorithm, the output can be switched in percentage, between values, with stepped control output, output can be five points in any setting, single button control is more suitable for battery powered power supply use.)