Application Research of S7-1200PLC in the Automatic Control System of G120 Frequency Converter Speed Regulating Motor

In this paper, PROFINET is used to connect Siemens S7-1200 and G120 frequency converters together to form a control system for multiple induction motors. The interaction with the user is completed on the HMI platform. The system uses CSM1277 as a micro switch, and the three devices use Ethernet for communication. The communication between Siemens S7-1200PLC and G120 frequency conversion speed control device has been carried out via PROFINET. The predefined interface macro control communication scheme in the digital input interface of the frequency converter is used to realize the multi-stage speed operation of the three-phase asynchronous motor. This control system has the advantages of low cost, reduced number of cables, and multiple motors can be controlled independently at the same time. Motor running status can be displayed in real time. The stability, reliability and flexibility of the control system have been greatly improved.