Measurement and control system for variable-frequency speed regulating of motor based on PLC and HMI

The variable-frequency speed control system based on PLC has many advantages of PLC and VFD, which is one of the most ideal and promising speed control methods for three-phase asynchronous motor. Focus on the problem that the control system for variable-frequency speed regulating of motor base PLC is difficult to monitor the operational status of the PLC and the VFD in real time. This paper presents a measurement and control system for variable-frequency speed regulating of the motor based on PLC and HMI. Firstly, an intelligent measurement and control system scheme for variable-frequency speed regulating of the motor based on PLC and HMI is presented according to the design ideas and the composition principle of typical electrical control system. Secondly, the motor drive circuit and VFD control circuit are designed, and based on this, the control program of PLC and monitoring interface of HMI are developed. The test results show that the system design is reasonable, the operation is stable and the human-computer interaction interface is friendly, which can solve the above problems well.