Thread: Basic difference between PLC & uC

Hi all,

What is the basic difference between PLC & uC?

Thanks

hi
plc is a industrial mcu.
it has industrial properties such as isolated IO, high voltage power supply and etc.
noise of environment can't effect on PLC.
and many properties.

Microcontroller has more powerful functions, as the programming of microcontroller is more complicated than PLC. PLC has high voltage but microcontroller has small voltage, usually 3V-5V.

A PLC is a modular device which one can program using Ladder diagrams (relay logic) or Statement List (a bit like assembly). It is optimized to handle several digital inputs and outputs, and is more rugged for use in industrial applications. Basically it scans the inputs, and determines the outputs based on the logical conditions programmed into it by the user. It internally uses a microcontroller to handle all input, output and logic scans. Application area is mostly industrial automation.
Microcontrollers are cores that will do anything you program them to do. They probably can be used in each of the above applications, but with varying effectiveness. As always, your work is in discerning which option will work best in a given situation.
...
Regards,
IanP

My opinion is that basic difference between PLC and microcontrollers is only the way of programming. Most common way of PLC programming is with graphical language – Lader logic programming which looks a little similar more to electrical schematics than a computer programming language. There is and some not so mass ways like functional block diagrams, as well Mnemonic (like assembler), stages etc. Second significant characteristic is the infinite loop (cycling) through the lader start-to-end and again from start… Normally the algorithm is read inputs-solve the logic – update outputs and again. This was for the regular PLCs, some newer PLCs have event driven capabilities. Also PLCs are more restricted in calculations (as they normally dont need it)