WHAT IS THE DIFFERENCE BETWEEN PLC AND DCS

Answer Posted / ravi kant anand

There is a chip inside PLC which is burnt with logics as
per requirement of process and once the chip is burnt after
that you can only modify the logic or even you can include
single I/O by reburning the chip only in shutdown of
process "not in running process",second option could be to
include separate PLC for including even single signal in
running process. but in case of dcs you can include, modify
or change the logics, even in running process by
downloading into controller.
finally we can say, it would be better
to use PLC if you are quite sure that there would not be
any inclusion, modification or change in logic for the
process otherwise DCS would be smart choice.
generally for small process we could
be sure that there would not be any inclusion, modification
or change in logic for the process so most often we use
PLC, but for large process like handeling the process of
whole power plant, logic inclusion, modification or change
is often so dcs would be better choice.

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