这个是vb 的一个控件，对用于vb画图软件很有用！-This is is for beginner students of several experimental SCM! They would be very helpful!

水位控制的上位机VB编程，采集到当前水位，发送至PC机，可以设定上下阈值，并对于阈值及其当前数据画图-VB programming, water level control of the upper machine to collect to the current level, sent to the PC, can set the upper and lower threshold, and drawing for the threshold value and the current da