基于PLC的双容水箱液位串级PID控制的实现

Implementation of cascade PID control for double-capacity water tank based on PLC

文章以双容水箱为被控对象,S7-200PLC为控制器,设计了双容水箱的液位串级控制实验。液位信号经液位变送器送至PLC,采用PID算法对数据进行处理,之后输出至电动调节阀来实现对液位的控制。采用一步整定法确定了主、副控制器的最佳PID参数。用MCGS作为上位机组态软件,构建了对双容水箱液位进行实时监控的组态画面,画面直观、形象,能实现液位的准确控制。

With double-capacity water tank as a controlled object,ST-200PLC as a controller, the paper designed the cascade control experiment of liquid level of double-capacity water tank. Liquid level signal was sent to PLC by liquid level transmitter, using PID algorithm to process the data and then output to the electric control valve to achieve the liquid level control. The experiment confirmed the optimal PID parameters of the main and sub controller by using step tuning method. Taking MCGS as upper unit configuration software,the experiment constructed a configuration screen for real-time monitoring of double- capacity water tank. The screen is intuitive and visual and the system can achieve accurate control for liquid level.