Answer / eswar

Plc is a simple computer which used for automation of real
world processes such as controlling of machinery in a industry.
Plc is a microprocessor based device with input and output
circuitry that monitors the status of the field connected
"sensor"inputs and controls attached output"actuators"
according to user created logic program.
application: maintaining the water level in a tank between
two float switches by controlling the electric valve.
Ladder diagram is a language which composes of program using
a relay logic symbols as a base in an image similar to a
hardwired relay logic sequence.
advantages
flexibility,pilot running,space efficiency,correcting
errors,visual observation

Answer / abdul ahad

I am Agreed with Answer # 1 and 2 .
PLC is Programable Logic Controller and we can used it for
any kind of the industries/home automation or semi-
automation ( As per our requirement ).

Answer / ankit arora

ladder programming is a language . ladder language is a
combination of input contacts and output coils for make a
logic programm.

Answer / priyaloges

The PLC is a controller device which is used to control the
logically automated systems.It replaces relays to a single
PLC.Fuctions are motion control, process control, networking
control,distributed controletc.,

Answer / nilesh yadav

A PLC has many "input" terminals, through which it
interprets "high" and "low" logical states from sensors and
switches. It also has many output terminals, through which
it outputs "high" and "low" signals to power lights,
solenoids, contactors, small motors, and other devices
lending themselves to on/off control. PLCs are industrial
computers, and as such their input and output signals are
typically 120 volts AC, just like the electromechanical
control relays they were designed to replace. Although some
PLCs have the ability to input and output low-level DC
voltage signals of the magnitude used in logic gate
circuits, this is the exception and not the rule.

Answer / himanshu patel

>A programmable Logic Controller (PLC) is a solid state/computerized industrial controller that performs discrete or sequential logic in a factory environment. It was originally developed to replace mechanical relays, timers and counters. PLCs are used successfully to execute complicated control operations in a plant................!!!

>It is field programmable by the user. It allows the user to modify the programs as per the requirements of a plant without having to send the unit back to the manufacturer for this purpose.
>Plant Automation is the necessity for the manufacturing industry to survive in today’s globally competitive market.

Answer / muthu kumar

PLC is a kind of processor which we can it use for any
applications, ladder diagram is a language which plc can
understand. there are so many advantages are there we can
use it for any applications but it is depends upon the user
needs and I/O of PLC.

Answer / dhara

A Programmable Logic Controller, or PLC for short, is simply a special computer device used for industrial control systems. They are used in many industries such as oil refineries, manufacturing lines, conveyor systems and so on. Where ever there is a need to control devices the PLC provides a flexible way to "softwire" the components together.

Answer / denish pastagia

Its Programmable Logic Controller, its a one kind of industrial Computer which is use to interface between Field input device and field Output Devices, Its Made for work in rough Environment, its microprocessor based Controller, With the using of Plc We can Develop Any Kind of Application like car manufacture unit, Bottle Filling Plant through Programming,
In Industry the mainly Use of PLC is like a main Controller Though Which We Controlled Every Instruments.
Its Reduces the Wiring Cost And The use of Plc We Easily Troubleshooting the Concept and Hardware. 

Answer / shanmugaraj s

plc is programble logic controller , plc main use of real
tmie relay and timier and counter is replacedto the fully
programing use. the main application of all industry
automation is using plc ladder diagram.convery control,
water filling control , counting application , fully
automation process.. plc advantage is flexiblity,compact
size, program is very easy, easily control the all component

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