In the process industries there is an ongoing need for improvement of the opera­ tion of the process. One of the disciplines that will help the process engineer to achieve this is process control. There are many industrial automation systems to­ day that will offer powerful tools to meet the process control needs of industries with continuous, batch and discrete operations. Advanced control solutions sustain and improve the plant's competitiveness by ensuring: - safe operations - compliance with environmental regulations - effective use ofraw materials and energy - efficient production - manufacturing ofhigh quality products - flexible accommodation ofchanging process requirements This book was written from the perspective of introducing advanced control con­ cepts, which can help the engineer to reach the aforementioned goals. Many ad­ vanced control techniques have been implemented in industry in recent years, since hardware and software platforms are becoming increasingly powerful. Manufacturers ofprocess control equipment call this hardware and software envi­ ronment generally 'distributed control system'. The distributed control system equipment offers the engineer an excellent plat­ form for writing and implementing advanced control solutions. However, most large chemical and petrochemical manufacturers hire control specialists to imple­ ment these control solutions, while small manufacturers often lack the funds to hire these professionals. Therefore it is our experience that in the latter case, proc­ ess engineers often write the control programs required to improve process opera­ tion.