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

what is the diffrence between mmwc and kg/cm2 for pressure measurment when we are using mmwc and when kg/cm2 and why????? ?? what is the reason

19 Answers   Ecoboard, Jindal, Sepco,

Draw a group of instruments interlocked to a Pump & Motor?

0 Answers  

A temperature sensor (RTD) connected via a temperature transmitter is adjusted to give an output of 4ma at 60 deg and 20 ma at 600 deg. This output (4-20ma) from the transmitter is connected to an IGBT-inverter to control a high speed (-12,000 to +12,000 RPM) DC motor. And in the inverter it is programmed as, for 4ma the motor speed will be -3,000 RPM and for 20ma the motor speed will be +10,000 RPM. The question is : If the motor speed is +5,500 (RPM), what will be the temperature? (-sign indicates that the motion is in reverse direction).

9 Answers  

how u measure flow?orifice measurement?why all ft in square root?

1 Answers  

what is Least Value of MICROMETER?

3 Answers  

How can we measure the level of a closed system like drum

3 Answers  

Dear All can any one told me that VFD Make ABB Model ACS800-01 used for dual Source like 1.DC Source applied at terminal UDC+,UDC- 2. 3 phase 400AC,50Hz

1 Answers  

Decibel.

0 Answers   CCIE,

If we interchange HP and LP tapping in drum level measurement and reverse LRV & URV correspondingly.What is the difference between the normal tapping(HP,LP) and reversed tapping(LP,HP)?

2 Answers  

What is the meaning of Feedback? How many types it is? Explain it?

2 Answers   Bharathi Cement,

What's the difference between cold loop test and hot loop test?

5 Answers  

What is voltage free(wet) and potential (dry) contact?

2 Answers