Question: Sketch the root locus diagram for the analyzer control loop of Problem.

Problem: Calculate the ultimate gain and period of oscillation for a proportional analyzer controller installed on the blending tank of . The control valve is to be installed on the dilute stream and sized for 100% overcapacity. The valve has linear characteristics, has a constant pressure drop of 5 psi, and can be represented by a first-order lag with a time constant of 0.1 min. The analyzer transmitter has a range of 20 to 70 kg/m3 and can be represented by a first-order lag with a time constant of 3 min. Also draw the block diagram of the loop, showing all transfer functions, and calculate the offset caused by a change of 0.1 m3/min in the flow of the concentrated solution when the controller gain is one-half the ultimate gain.