说明：  数字电压表是基于PSOC实验平台设计的，能够测量0—5V的电压，具有门限报警功能。电压表能把电压值实时的传输给电脑。同时，电脑也能对电压表进行开、关和设置门限电平等控制。
(Digital voltmeter design based on the the PSOC experimental platform, capable of measuring 0-5V voltage threshold alarm function. The voltmeter can real-time voltage transmitted to the computer. The same time, the computer can also voltmeter on, off and set the threshold equal control.)