Application of Linked Personal Computers for Automatic Control in Large Sewage Works
So far only very large sewage treatment plants (STP) are equipped with real process computers. High investment costs and complicated handling prevented their application in medium-sized and smaller STPs. Meanwhile Personal Computers became so efficient and reliable that they can be used for automatic control of industrial processes. In this paper the successful enlargement of the central STP of Stolberg-Steinfurt for 120,000 inhabitant equivalents is described. In the central facility seven linked personal computers co-operate in a local area network (LAN) for monitoring and optimization of different processes. They are connected with seven programmable controllers in outstations on site. The data transfer between the central control room and the outstations takes place using RS 232 C interfaces. Because of the use of common office computers in combination with industrially proved controllers the operators very soon accepted the system. After one year of operating experience they assess the system as a valuable tool.