The Companhia Vale do Rio Doce (CVRD) is one the world biggest company in production and exportation of iron ore. The Cauê plant provides 20 millions of ton of natural ore per year. The company asked smar to start-up an automation and control project of hematite and itabirite desliming plant at the Companhia Vale do Rio Doce (CVRD) - Cauê plant, in Minas Gerais state, Brazil. This project was implemented using the PROFIBUS technology and it was the first experience in using fieldbus at the CVRD south mining system, where the aims are to provide a higher revenue of production process, to reduce partially the labor, to provide an efficient control in the granulation partition and a higher operational flexibility.
The itabirite desliming plant has the following instruments: 5 Pressure Transmitters (smar), 5 PLCs (Schneider) and 20 On-off control valves (ITT). The hematite desliming plant has the following instruments: 6 ultrasonic level transmitters(E+H), 2 Flow magnetic transmitters(E+H), 6 continue control valves from Masoneilan with smar positioners, 2 density transmitters(TN) working integrated to the 4-20mA to PROFIBUS PA converter(Smar), 6 Pressure Transmitters(Smar), 2 frequency inverters (WEG) and 10 solenoid valve control units (REXROTH).
The PA devices are integrated into PROFIBUS DP system using DP/PA couplers (P+F) All system is integrated into Quantum PCL(Schneider). An important point is the integration between Profibus PA devices and 4-20mA devices using the current to Profibus PA converter from Smar.
Although the presence of different manufactures on the bus, the system interoperability and startup were excellent and the plant is operating very fine.
According to the CVRD automation engineer Miroslav Bires, the PROFIBUS network advantages concerning to the cost reduction and simplicity were confirmed and nowadays they are observing the maintenance behavior that until this moment shows a great performance crediting future projects at CVRD using PROFIBUS technology.