Difference between PLC and DCS

PLCs are can respond to a change within one tenth of a second

DCS are slower than PLCs. Typical respond time of DCS is 30ms

A PLC is capable of handling few hundred IOs. It can handle tens of them.

A DCS can handle thousands of IOs. It can handle hundreds or even thousands of analogs IOs and PID functions

PLC can programmed be programmed based on our application

DCS comes with built in control functions that need to be configured based on the application

PLCs can be made redundant with additional hardware which makes them expensive than DCS

Redundancy is a default feature of distributed control systems.

PLCs have a simple and flexible architecture. A PLC system consists of controllers., IO modules, HMIs and an engineering software.

DCS system are less flexible. They come with controllers, IO systems, database servers, engineering and operating servers.

PLCs are best suited for dedicated applications that changes less often.

DCS is suitable for complex processes that require advanced process control capability

Less expensive

More expensive