SOLUTIONS

1. ERT 321Process Control & Dynamics EXERCISE 3 SOLUTIONS Anis Atikahbinti Ahmad

2. In this question, a model is not given. Thus, we have to develop a process model from the experimental data. At time = 1 min, there is no change in temperature data. Thus, we know that time delay term should be included in our model.

3. From the reaction curve, we know that our process model is in the form of first order plus time delay (FOPTD);where You have to find K, τ and θ given in the question You have to find

4. Process output (Temperature, ° C) Transmitter output (Temperature, mA) Process input (Pressure, psi) Transmitter input (Temperature, °C) Process output (Temperature, ° C) Transmitter output (Temperature, mA) Transmitter output (Temperature, mA) Process input (Pressure, psi) Transmitter input (Temperature, °C) Process input (Pressure, psi)

5. Thus,

6. (a)ITAE (setpoint change) From ITAE Performance Index Table, PI controller 12

7. (b) Direct Synthesis method with τc= τ/3 From Table 12.1, PI controller

8. (c) Ziegler Nichols Use characteristic equation. Use proportional only controller, Gc= Kc (1) Using 1/1 Padé Approximation, substitute e-1.6s = into (1)

9. Substituting and Direct substitution method Equating imaginary and real coefficients;