a) What is Stiction and how does it occur in control valves? (2 marks) b) Explain what happens when Stiction is present in a control valve and show a graph which illustrates the controller ouput where the process has a large time constant or an integrating process. (4 marks) c) How does the use of a digital valve controller help diagnose the presence of Stiction? (2 marks) a) Stiction is static friction on the control valve shaft, this causes moveme