Terminology and
Symbols in Control Engineering
Technical Information
Part 1: Fundamentals
Part 2: Self-operated
Regulators
Part 3: Control Valves
Part 4: Communication
Part 5: Building Automation
Part 6: Process Automation
Terminology and
Symbols in
Control Engineering
Introduction . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . 5
Terminology in Control
Engineering . . . . . . . . . . . . . . . . . . 6
Open loop control . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Closed loop control . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Process . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Control loop . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Abbreviations of variables
relating to closed loop control. . . . . . . . . 10
Symbols in Control Engineering
. . . . . . . . . . . . . . . . . . . 12
Signal flow diagrams. . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Blocks and lines of action . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Device-related representation.
. . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Instrumentation and control
tags . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Control Systems and Structures
. . . . . . . . . . . . . . . . . . . . 22
Fixed set point control . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Follow-up control . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Cascade control . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Ratio control . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Appendix A1: Additional Literature
. . . . . . . . . . . . . . . . . . 26
