Consider proportional-only control of the stirred-tank heater control system in Figure. The temperature transmitter has a span of 50°F and a zero of 55 °F. The nominal design conditions are T = 80 °F and T₁ = 65 °F. The controller has a gain of 5 while the gains for the control valve and current-to-pressure transducer are K_v =, 1.2 (dimensionless and K_/P = 0.75psi/mA, respectively. The time constant for the tank is τ = 5 mm. The control valve and transmitter dynamics are negligible. After the set point is changed from 80 °F to tank temperature eventually reaches a new steady-state value of 84.14 °F, which was measured with a highly accurate thermometer.

(a) What is the offset?

(b) What is the process gain K₂?

(c) What is the pressure signal p to the control valve at the final steady state?

Transcribed Image Text:

T'(s) K2 та E(s) (mA] туря) P(s) [psi] PAs) Kip Гpsi] P'(s) K, K. [°F1 Кл, [mAI TS + 1 (°F) ImA] 의사품 т's) [°F] (mA]