Programmable Logic Control

This equipment is very common in industrial over the world.It use in many equipment and machinery.It make the processing more easier to handling.

In general,PLC  is a collection of electronic device which are in  place to ensure the stability,accuracy and smooth transition of a process or manufacturing activity.The relay,timer,counter,preset counter and many more control device built in this device.We can integrate with many output device  like motor,solenoid,heater,lamp,buzzer and etc.

We can use the software to create the wiring control very easy and just use the symbol or icon in the diagram,we can control anythings.The software are depend on manufacturing of PLC likes mitsubishi ( GX-Developer ),Keyence ( KV Builder ),OMRON ( Syswin ),SEIMENS ( Mirco win ),LG ( KGL WIN ) and etc.I will discuss about PLC SOFTWARE more in my next post :D



Description of PLC.

They have a three ( 3 )  important components to make it functioning properly.


– Intelligence of automate system is depending on ability of PLC to read in the signal from various type of automatic sensing and manual input device.

Manual input device : Switch button,toggle switch,push button,emergency button,keypad and ETC

Detection Device : Proximity switch,limit switch,photoelectric sensor,level sensor, or any type of sensor for monitoring of moving,flows,pressure and others.


-An automatic system is incomplete and the PLC system is virtually paralyzed without mean of interface to the field output device.

The most commonly controlled device like :

  • motor
  • solenoid
  • lamp
  • motor stater
  • heater
  • LED display;etc

3) Central processing unit ( CPU )

-This is the most important part of PLC.all programs for the control circuit save in this part.It is a microprocessor that co-ordinate the activities of PLC system.It execute the program,process Input/Output signals and communicates with external device.

Types of PLC Memory 

They a various type of memory.It is area that hold the operating system and user memory.The operating system is actually the system software that co-ordinate the PLC.Ladder program,timer and counter value are stored in the user memory.Depending on users need,various type of memory are available for choice :

  • Read Only Memory ( ROM )
  • Random Access memory   ( RAM )
  • Erasable Programmable Read Only Memory (EPROM)
  • Electrically Programmable Read Only Memory (EEPROM)

I will explain detail about PLC PROGRAMMING in my next post :D

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