液位PID控制系统的设计

Design of liquid level PID control system

针对工业生产中对恒定液位的储水系统的需要,本文介绍了一种水池恒液位的PID控制系统的设计,该系统利用西门子S7-200PLC的PID指令实现对液位的PID闭环控制,利用液位传感器将液位的值作为反馈信号传给PLC,以设定水位值和反馈水位值之差作为PID控制器的输入,控制器的输出是频率信号,并对变频器进行调节控制,而变频器对电机实现转速调节,最后通过VB软件进行特性测试。通过检测本系统准确、快速实现了液位的恒定控制。

Many reservoir systems of constant liquid level is needed in manufacturing production.The design of constant liquid level PID control system was introduced in this paper.PID closed loop adjustment control of liquid level was accomplished by the order of PID in s7-200PLC.PLC received the signal from liquid level sensor as feedback.PID Controller which get the signal of the difference between setting liquid level and feedback give the signal of frequency to the Frequency Converter.The Frequency Converter was used to regulate the speed of motor.By the characteristic tests of VB,the system kept the constant of liquid level accurately and quickly.