Q3.(A) Explain EACH of the following control terms
(i) Proportional action (2)
(ii) Integral action (2)
(iii) Derivative action (2)
(B) Explain why proportional, integral and derivative actions are combined in one controller (PID), stating an example where it may used. (4)
Q2. With reference to pneumatically operated control valves:
(a) state FOUR the reason for fitting valve positioners; (4)
(b) explain valve hysteresis, stating how it affects the process; (2)
(c) state the immediate action to be taken to restore control upon failure of the positioner bellows; (2)
(d) state the difference between fail safe and fail set (2)
Q3. With reference to automatic control:
(a) Sketch a pneumatic proportional plus integral controller;?? (6)
(b) Explain the term integral saturation; (2)
(c) Explain the action to be taken by the operator in the event of integral saturation occurring. (2)
Q2. With reference to automatic control systems:
(a) explain the term proportional band width; (2)
(b) state how the proportional band may be adjusted on EACH of the following:
(i) motion balance controllers (2)
(ii) force balance controllers. (2)
(c) explain the consequences if the proportional band is set incorrectly. (4)
Q2. (a) State, with reasons, the control actions that may be suitable for EACH of the following processes:
(i) settling tank oil temperature; (2)
(ii) jacket water temperature; (2)
(iii) temperature of oil being purified. (2)
(b) Sketch a block diagram of ONE of the control circuits for ONE of the processes in part (a). (4)
Q2. (a) Explain EACH of the following control terms:
(i) cascade; (2) (ii) split range. (2)
(b) Describe, with the aid of a sketch, a control system that may be enhanced by the inclusion of cascade control. (6)
Username or email address *Required
Password *Required
Note: Entering wrong username in the login form will ban your IP address immediately. Entering wrong password multiple times will also ban your IP address temporarily.
Log in
Lost your password? Remember me
No account yet?
