Research Of The Control Methods In Whole Line Mode For BIW Welding Line

Huge amounts of equipments make the structure of BIW robot welding line very complex. In order to make actions between machines and machines, and actions between machines and robots smoothly and orderly, what's more, to ensure the welding line running with safety and reliability, a great deal of PLC program codes are needed. In order to make the maintenance and servicing of electrical hardware easily and enhance the reliability of the hardware, this paper uses distributed I/O modules which based on Field Bus technology and the Safety I/O modules based on Safety Field Bus, to cutting down the cost and increasing the flexibility of the whole line. In order to make the programming work high-efficiently and the PLC program more logical, this paper uses the ideas of modularization to plan the PLC project for the whole welding line and the ideas of Object Oriented method in high-level program language to build interface and control variables for every special machine, and also for some logic units for operation, cycle, sequence controlling and etc. Based on the interfaces and control variables, the control codes for the machines are modularized. When writing PLC program for a welding line, it's very convenient to combine the program modules to a software project. The frame of software project is brief and the readability of the software is enhanced as using this method, which make it easy to be serviced and understood by the engineers.