FEEDBACK CONTROL SYSTEMS UPDATED ACTUAL QUESTIONS AND CORRECT ANSWERS COMPLETE STUDY GUIDE FULL SOLUTION

FEEDBACK CONTROL SYSTEMS UPDATED
ACTUAL QUESTIONS AND CORRECT
ANSWERS COMPLETE STUDY GUIDE FULL
SOLUTION

●● feedback control loop
Answer: the variable to be manipulated is measured


●● Process Controllers
Answer: most dynamic device in a feedback control loop
• They compare the process variable with the set point and generate an
output signal that manipulates the process to make the process variable
equal to its set point.


●● Types of controllers
Answer: Pneumatic
Electronic
Multiloop
Programmable logic
Single Loop


●● Pneumatic

,Answer: Automatic controller that uses variable air pressure as input and
output signals


●● Electronic
Answer: Also called digital controllers


●● Multiloop
Answer: Contain a variety of function blocks that can be soft-wired
together to form complex control strategies


●● Programmable logic
Answer: Was first used in automotive industry and offers a limited
number of math functions


●● Single Loop
Answer: Process controller that produces a single output


●● Advanced Control Loops
Answer: Cascade Control Loops
Ratio Control Loops
Feedforward Control Loops


●● Cascade Control Loops

, Answer: The general concept of cascade control is to place one feedback
loop inside another. In effect, one takes the process being controlled and
finds some intermediate variable within the process to use as the set
point for the main loop.


●● Ratio Control Loops
Answer: often associated with process operations in which two or more
streams must be mixed together continuously to maintain a steady
composition in the resulting mixture.


●● Feedforward Control Loops
Answer: sensor is used to detect process load changes or disturbances as
they enter the system. Feedforward control poses some significant
problems. more complicated and more expensive, and it requires the
operator to have a better understanding of the process than does a
standard feedback control loop. generally reserved for well-understood
and critical applications.


●● Components of a Control System
Answer: Process
Measuring Element
Controller
Final Control Element


●● Closed-Loop System or a Feedback System