chapter14

Chapter 12 PRACTICAL APPLICATION OF FEEDBACK

Check Your Reading Study Questions Thought Questions

The questions will be categorized according to the key concepts in the Chapter.

Input Processing	Control Equipment
Output Processing	Controller Calculation

Check Your Reading

Solidify the Concepts

12.1
All control valves used for pressure control should be fail open to prevent pressure buildup.

TRUE FALSE

12.2
Consider the situation in which a control loop has been functioning well; then, the failure position of the valve was switched. What would have to be changed in the computer algorithm?

	Nothing should be changed.
	Need to complete the tuning procedure (reaction curve and calculations).
	The gain should be reduced to prevent oscillations.
	The controller sense switch should be changed.

12.3
If we average many readings from a sensor with excellent reproducibility, we will obtain a value very close to the true process variable.

TRUE FALSE

12.4
Measured values should be filtered to smooth sensor noise before being displayed on trend plots.

TRUE FALSE

12.5
Using proportional band (PB) and reset time (T_R) in the PID algorithm can dramatically improve control performance.

TRUE FALSE

12.6
Commercial digital control systems have controller gains that are always greater than or equal to zero.

TRUE FALSE

12.7
When the controller is placed in service, which of the following are performed as part of the initialization?

	Set the error to zero.
	Set the integral error to zero.
	Calculate the bias (I) so that the manipulated variable does not change.
	Calculate only the proportional mode for the first execution; then, calculate all modes thereafter.