Answer / deepak

These are the major differences
1. scanning time of a PLC is depend upon the length and size of the program. In DCS scanning time is constant.
2. DCS can handle large number of IOs

Answer / lalit dongre

PLC is mainly used for sequential control but dcs is a distributed control it can handle many process in one time also DCS Has redundancy feature so that the process cannot Stop due to power failure.  

Answer / sumit_110386

PLC Simplified with limited logic control for like a
machine or Simple process with limited interlock logic -
progamme can be modified easily.& also proto type.This will
give only indication of faiiure.No recording the event or
process parameter ,with limited memory.Cost wise it is very
cheap

Dcs concern Huge multiple logic controlls with >1000 of
inter lock for process of power plant or refineries or any
process Industries it will give all types of alarm in soft
copy & hard copy about process , failure & record all the
process input & out put parameters & efficiency if
required .(like Boiler,Turbine, Generator controlls Switch
gear cotrolls ie power generation to Transmission It will
cover up everything) Very huge memory back up, failuer rate
very less.process parameter all are fixed cannot be changed
by Individual. Troube shooting very easy .production will
not be affected at all .( (stand by system will take care
automatically change over)Cost will be very high.

Answer / faiyaz ahmad

PLC.stand for programmable Logical Control its industrial computer which is used monitoring and control the field instrument means more number of Input out put
DCS stand for Distributed control system means monitoring and controlling more number of input and out put its control the one unit of plant.

Answer / linu mohan

PLC-Programmable Logic Controllers

DCS-Distributed Control Systems

Different no. of PLC's contribute together to make
a DCS system

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