Chapter 8    The PID Algorithm


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

Block Diagrams PID Algorithm

 

 

 

 

 

 

 

 

 

 

 

 

Check Your Reading

Solidify the Concepts
8.1
The three modes of the most common feedback controller are called the...		  


 

 

 

Persistent

 

Integral

 

 Proportional

 		 

 Derivative
 

 Interacting

 		 

 Disturbance
 

 

 

 

 

 

 

 

 

 

 

 

 

8.2
In explaining the PID controller, the term mode means...

PID Algorithm




 

  

the highest profit attained with control.

 

 an adjustable parameter.
 

 a specific method of considering time-dependent behavior.

 
has no meaning, only included to confuse students.

 

 

 

 

 

 

 

 

 

 

 

 

8.3
A block diagram is useful for...

Block Diagrams

 

 

 

 

 

 

 

determining the overall transfer function model of the closed-loop system.

 

 providing a visual display of the elements in a closed-loop system.
 

 developing some general properties of closed-loop systems, e.g. determining which elements affect stability.

 

 

 

 

 

 

 

 

 

 

8.4
Which element of the closed-loop, feedback system does NOT affect the stability of the closed-loop, linear system?

 

 

 

 

 

 
 

 

 

Gd(s); disturbance

 

Gs(s); sensor

 

 Gc(s); controller

 		 

 Gv(s); valve
 

 Gp(s); process

 

 

 

 

 

 

 

 

 

 

 

8.5
The error is calculated as E = SP - CV (not E = CV - SP).  The choice of sign is...


 

 

 

arbitrary.

 

 to ensure that the value of the error is greater than or equal to zero.
 

 needed when the set point value is changed.
required for negative feedback.

 

 

 

 

 

 

 

 

 

 

8.6
What is the sign of Kc for negative feedback control?


 

 

Positive

 

 

 Negative
 

 Same as Kp     (the process S-S gain)
Opposite of Kp  (the process S-S gain)