Design And Research Of The Site Environment Monitoring System In Automobile Paint Plant

China’s automobile manufacturing was developing rapidly in recent years. Various joint venture brand passenger cars and commercial vehicles production base projects have been put into use. Painting play an important role in automobile manufacturing, and the process of site environment provides a suitable environment for craft spray,staff working and equipment operating.This paper deeply studies monitoring system of site environmental in automotive paint shop by using industrial process control systems technology as the theoretical guidance and reference.The monitoring system consists of 12 PLC control systems and 32 PCs,PROFINET was used as a communication network for data exchange between devices. The control slave distributed I / O devices ET200 S combined with the master controller PLC,which forms a distributed control system, by configuring the PN / PN Coupler, we achieved the interlock control of PLC.The PLC user program was compiled with structured programming approach,which is not only convienient for unified project management, but also reduce the programming and debugging work. Involving a large number of analog processes in the site of environmental monitoring systems, this paper have a detailed study of the Siemens S7-300 series PLC in analog processing hardware and software programming and further study of the PLC on closed loop PID control function blocks for analog value control process. SINAMICS G120 inverter was used as a PLC output control signal actuator. this paper made a thorough study on the data exchange between inverter and PLC and also made a detailed analysis on the use of closed-loop PID PLC control the drive frequency to achieve a constant air volume control process.The system used “centralized monitoring, decentralized control” model, each PC can scan the status and data of multiple PLC control system. Using configuration software Win CC as a development tool, the OPC technology was used to build client / server redundancy systems, which increased the availability of Win CC and equipment. Friendly interactive interface design, Maintenances of the production process can quickly deal with faults to ensure production task is completed in time.