Answer / madhukar vangari

PLCs were designed to replace Relay Logic System with only
digital inputs and outputs early 60s whereas Dcs was
designed to cater the requirement of heavy process
industries with only analog inputs and outputs.

Nowaday PLCs are started having analogue I/Os and DCS with
digital I/Os.

Plcs execute sequential program and executes one program at
a time where as Dcs is multitasking in nature.

In plc PIDs are required to be tuned whereas PIDs are tuned
automaticaly in DCS

SCADA is integral part of DCS ,in case plc SCADA
needs to be designed with different scada software.

Answer / ak khan

DCS have multiloop controller, distributed I/O
sub-stations,complex process control capabilites while PLC
is use for specific work, limited I/O terminal & memory

Answer / ses

Re: WHAT IS THE DIFFERENCE BETWEEN PLC AND DCS
Answer
# 23 DCS is nothing but connecting more PLC'S in a network
and
monitoring it in a control station. The main difference is
in DCS it has in-built SCADA so it is user friendly whereas
in PLC we need to get a SCADA software.

Answer / rupak sharma

plc has limited I/O's (limited Expansion module) but in DCS System There are Unlimited I/O's in the dcs we only change its dongle And operate it, there is a another difference in DCS and PLC in the DCS system redundancy factor is available but in the plc no redundancy factor is present

Answer / sajjad mahmood

plc,s programing in ladder logic and DCS programing in many
languages or software.

Answer / d.arumuga selvan

The difference between PLC&DCS is that, PLC is a small scale control system which mainly deals with ON/OFF control of a single machine......... but dcs is a large scale control system which controls all over the industry units... simply i can say dcs is a network consists of many plc units...

Answer / sam........

PLC IS SINGLE PROTOCAL AND SINGLE CPU SYSTEM AND USED FOR
SPECIFIC AREA ONLY NOT FOR OVER ALL PLANT CONTROL

DCS IS MULTI PROTOCAL AND MULTI CPU SYSTEM USED FOR OVER
ALL PLANT CONTROL

Answer / haris

basically plc and dcs are same. difference depends on
industrial uage. plc is used for start-up/shutdown
processes, batch process; dcs used for controlling output to
match set point

Answer / shan

The difference between DCS and PLC is that, PLC is
primarily a small scale control system which only executes
only digital function. When we say DCS, It is a networks of
PLC's,it is a large scale control system which is
distributed all over the plant,and is located in a control
room.

Answer / bantaa

A distributed control system (DCS)is a control system usually
of a manufacturing system, process or any kind of dynamic
system, in which the controller are distributed throughout
the system with each component sub-system controlled by one
or more controllers. The entire system of controllers is
connected by networks for communication and monitoring.

Where as the PLC system is the sub system controller.
Ex- If we consider a thermal power plant, then there is
several sub-system controllers are present, which is
controlled by PLC.

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