YME Engineering Course

A. INTRODUCTION TO PROCESS CONTROL SYSTEM
Display
Display
Computer
System
Printing
Computer
System
Printing
Process Variable (PV)
Setpoint
(SV)
Process Variable (PV)
Setpoint
(SV)
Tank
E/P
Manipulated
Variable (MV)
Tank
E/P
Manipulated
Variable (MV)
Figure: Data Logging
Figure: Set Point Control
As the introduction of computers into process control advanced, controller
functions were superseded by computers, and DDC in which computers directly
controlled processes began to be employed.
In the early stages, the control system was centralized where a central computer
executed not only monitoring and operation but also all process controls. The
most important reason was cost effectiveness.
The advent of microprocessors greatly changed the above situation. The study
theme moved to how diversification could be implemented (risk distribution,
function distribution, etc) and how exclusiveness and versatility could be united.
The distributed control system (DCS) now has inputs points distributed for 1 loop,
8 loops, 16 loops and upto 80 loops to be able to apply approximately when seen
from processes.
YME Training Center
A-5
CS3KR3-ENG 1 ST Edition Jan 2002