Greg McMillan is a retired Senior Fellow from Solutia/ Monsanto and an ISA Fellow. Presently, Greg is a principle consultant at CDI Process and Industrial contracting in DeltaV R&D for Emerson Process Management. Greg received the ISA "Kermit Fischer Environmental" Award for pH control in 1991, the Control Magazine "Engineer of the Year" Award for the Process Industry in 1994, was inducted into the "Control Process Automation Hall of Fame¿" in 2001, and honored by InTech Magazine in 2003 as one of the most influential innovators in automation. Greg is the author of numerous books on process control, his most recent being Essentials of Modern Measurements and Final Elements for the Process Industry. Greg has been the monthly "Control Talk" columnist for Control Magazine since 2002. Greg¿s expertise is available on the Web site: http://www.modelingandcontrol.com.