Answer / loganatha subash . m

The main difference is, Many PLCs can be controlled through
one DCS, but DCS cannot be controlled by PLC. For the large
plant DCS is the best than PLC.

Answer / arjunsinh k rathod

Generally PLC are used if your used I/Os are limited, like
steel and paper industries where no. of DI,DO, AI and AO
are limited on the otherhand in petrochemical processess
where I/Os are used in thousands of numbers then DCS is
useful.

Answer / preethi

PLC is used for safety purposes in a plant. It ensures safe
shutdown during abnormal conditions.
DCS is mainly used for data acquisition, monitoring and
control.

Answer / sharah beel

PLC
Performance drop with increase in loop count.
Complicated and lengthy Ladder programming.
Large engineering efforts are required incase of expansion.

DCS
No change in performance with increase in loop count.
It has FBD’s programming.
Re engineering efforts reduced by 75% in case of expansion.

Answer / jonny jain

1)PLC is small syetem in which no. of signals like DI,DO,AI,AO
are less and DCS is wwide system where no. of signals are more.
2)Working speed of PLC is high than DCS because no. of signals are less in PLC.
3)PLC used in small plant and DCS used big plant.
4)More no. of PLC are controled by one DCS

Answer / sooraj unnithan

Number of pid blocks are more in dcs compared to plc

Answer / harish

plc is use only for a machine,
dcs use for a big plant ,its operate a big plant at a time

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