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

2. In this question, a model is not given. Thus, we have to develop a process model from the experimental data. Time (min)T 2m (mA) 013 1 213.5 416 616.6 816.9 1017 1217 1417 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 questionYou have to find

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

5. Thus,

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

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

8. (c) Ziegler Nichols 1.Use characteristic equation. 2.Use proportional only controller, G c = K c Using 1/1 Padé Approximation, substitute e -1.6s = into (1) (1)

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