Distributed control systems divide plant or process control into several areas, each managed by its own controller connected through communication buses to form a single system. Localized control concentrates processing in one location using programmable logic controllers or programmable controllers, while distributed control uses remote terminal units with priority on data transmission and acquisition over local automation functions. In practice, either controllers or remote terminal units can take on roles typically associated with the other.

1. Evolution of NCS
Networked Control System

8. DISTRIBUTED CONTROL
SYSTEM
• A system of dividing plant or process
control into several areas of responsibility,
each managed by its own controller, with
the whole system connected to form a
single entity, usually by means of
communication buses..

11. Localized vs Distributed
Localized Distributed
Processing
tool
Programmable logic
controller / Programmable
controller
Remote Terminal Unit
Priority Data Acquisition
Local Automation
Data Transmission (Opt)
Data Acquisition
Data Transmission
Local Automation (Opt)
•Both PLC/PC and RTU support all automation functions only the
priority/ sequence differ.
•In practice, it is possible to use a Controller as RTU or RTU as
Controller