Valve characteristics Schedule on Controller output Flow GS Ref Line Discuss when this is appropriate Position The valve characteristics depend on the installation Schedule on process variable Schedule on external variable GS Ref LIC Discuss when this is appropriate Discuss when this is appropriate O K.J.Astrom and BWittenmarkValve Characteristics Flow Position Quick opening Linear Equal percentage The valve characteristics depend on the installation A B C Schedule on Controller Output FT FIC GS Ref Discuss when this is appropriate Schedule on Process Variable LT LIC GS Ref Discuss when this is appropriate Schedule on External Variable TT FT TIC GS Ref Discuss when this is appropriate c K. J. Åström and B. Wittenmark 6