What is the Difference between PLC and Microcontroller?

Hi Greeting,

Today we will talk about the difference between Programmable Logic Controllers and Microcontrollers. There is lot of confusion about using PLC’s rather than microcontroller especially students doing their projects in PLC’s will be asked about why they are using PLC instead of microcontroller?

Considering above point we will try to find out the solution.

Let’s start with the definition of PLC

Programmable Logic Controller (PLC) defined by NEMA as a digitally operating electronic apparatus that uses a programmable memory for internal storage of instructions for implementing specific functions such as LOGIC, SEQUENCING, TIMING, COUNTING and ARITHMETIC through digital or analog INPUT/OUTPUTMODULES.

Definition of Microcontroller.

Microcontroller is a microprocessor with internal input and output and memory i.e. RAM, ROM, PORTS.

Good things about PLC’s

  •     Its microprocessor based high end thoroughly developed Product for Industry which can be programmed through high end programming software uses its different simple to understand Ladder programming Language.
  •            PLC can be programmed to control anything from a power station to a small press. It has the requisite hardware and software to do this.
  •              PLC developed for Industrial Automation. 
  •     Development Time is less this seems to be cost effective solution in Service Industry.

  •      Troubleshooting a PLC system is much more technician friendly and very easy to adapt and change. Interfacing to a PLC is so much easier because it is designed for you basic machine signals, DC/AC, A2D, High Speed Input,serial and networking. With a microcontroller, you may have to design your own signal interfacing.
  •      PLC is a infinitely expandable input/output logic controller usually programmed with a external PC program

• They are highly reliable, fast and flexible.
• They can handle severe conditions such as dust, humidity etc.
• They can communicate with other controllers.
• They are easy to program and troubleshoot.
• They include display units.

Good Things about Microcontroller

  •   In case of Microcontroller the programming is somewhat tedious because of machine language.
  •   A microcontroller is also a logic controller but used in dedicated systems which are programmed once and for all, the program for which will not be accessed by the user, and whose program will not need to be altered frequently.
  •  Microcontrollers Developed for Dedicated equipments.
  •  Development Time is more.
  • With a microcontroller, you may have to design your own signal interfacing.
    Microcontroller is not a infinitely expandable input/output logic controller.

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