LIST OF FIGURES
Process Controls
LIST OF FIGURES
Figure 1
Open-Loop Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Figure 2
Closed-Loop Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Figure 3
Feedback in a Closed-Loop Control System . . . . . . . . . . . . . . . . . . . . . . . 3
Figure 4
Relationships of Functions and Elements in an
Automatic Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 5
Block and Arrows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 6
Summing Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 7
Takeoff Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 8
Feedback Control System Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 9
Lube Oil Cooler Temperature Control System and
Equivalent Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 10
Types of Oscillations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 11
Process Control System Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 12
Two Position Controller Input/Output Relationship . . . . . . . . . . . . . . . . . 18
Figure 13
Two Position Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 14
Relation Between Valve Position and Controlled
Variable Under Proportional Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 15
Proportional System Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 16
Proportional Temperature Control System . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 17
Combined Controller and Final Control Element Action . . . . . . . . . . . . . . 25
Figure 18
Controller Characteristic Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 19
Integral Output for a Fixed Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
IC-07
Page iv
Rev. 0
