Answer / eswar

PLC is a small computer used for automation of real world
process such as control of machinery on factory assembly
lines.where older automated systems would use hundreds or
thousands of relays,a single PLC can be programmed as a
replacement.
example maintaining of water level in a tank between two
float switches by opening or closing an electric valve.
In this example plc accepting two digital inputs from two
float switches.The plc controlling a single digital output
to actuate the inlet value valve into tank.
advantages:
1 flexibility:one single Plc can easily run many machines
2with plc we can do any changes in circuit design and we can
correct the errors.
3 pilot running
4 visible observation
5 space efficency: todays plc's have more memory therefore
we can generate more and more contacts timers,coils,counters.

Answer / siddhesh

plc is a combination of solid state devices 2 perform
specific task using ladder logic
plcs are used to control certain process like power plant
or cement plant
its more reliable than pc,cost efficent initial
installation cost is more,more precise results are
obtained,small size

Answer / prabodh kumar

Definition = It is such a real time memory based controller which cab be programmed logically a/c to our requirement.

Use= in controlling any type of operation of machines.
ex- packaging machine of food, braveries, water

Application= in controlling action of any kind of not only machines but also lighting system

Advantages= By using this we can do a lot of work in short of time ,
it is real time operated device,
we can increase i/p & o/p
we can erase the program.

Answer / radha

Plc is like a processor in a mobile phone ..it is used to control devices by programming

while i check zero check for dp flow transmitter some fluctuating came (0 to 458 kg/h) what is the reason?

0 Answers   Petronas,

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pt range is -45 psi to 45 psi.friends can you give answer with calculation and with linerity scale like 0%,25%,50%,75%& 100%?

1 Answers   WB,

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A PLC is programmed to drive three motors A, B and C as follows : After running motor A for an hour, motor B should get ON and motor A should get OFF. And after running motor B for an hour, motor C should get ON and motor B should get OFF. And after running motor C for an hour, motor A should get ON and motor C should get OFF. (That is, a cyclic repetition with time period one hour) Now, the second condition is: If any motor gone faulty and is tripped, the consecutive motor should get ON and the faulty (tripped) motor should be eliminated from cyclic repetition. The remaining two motors should bear the cyclic repetition of one hour each. (For healthy motor take logic as high and for tripped motor take logic as low) Now, the third condition is: When motor A load(Amps) exceeds 60% of its rated load, motor B should get ON in parallel to motor A. And when both motors A & B are running in parallel, and if their load exceeds 60% of their rated load, motor C should also start in parallel to A & B. [Here the cyclic repetition is eliminated, until their loads become normal(40%)] [Take logic high(1) for load at 60% and logic low(0) for load at 40%] Now draw a flow chart or a ladder diagram to fulfill the above condition.

0 Answers   MNC,

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During the design and engineering of a process plant, a good designer should plan for ____________, ___________ and ____________ aspects of the plant

1 Answers  

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how can we calibrate the differential pressure transmitter by using HART communicator

8 Answers   Hindalco,

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A length of steel pipe is used to carry sea water to a desalination plant. An adequate corrosion allowance must be specified and indicated in the piping specification, which affects the _________________________ of the pipe

0 Answers  

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how to check earthing,what is minum ohms for proper earthing

0 Answers  

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please tell no. & add. of consultancy who recruit me in power plant as instrumen engg. present i m working in power plant as ass.t instrument engg. thanku mahesh 09226562826

0 Answers  

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Please any one can explain how to calibrate transmitter (smart) online with out remove from the container suppose it is interface level or static pressure level measurement we dont want to remove transmitter from the container mean it is running plant please give me detail. thankx brothers

1 Answers   KNPC,

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deference between DCS and PLC including date processing and architacture.

11 Answers   Jindal, Shell,

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hw to calibration a control valve?

3 Answers  

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Can we use thermocouple in generator of power station replace RTD(pt 100)? if we don't have any place for use RTD.

2 Answers  

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