PLC vs. Microcontrollers

Which one is better in automating, using a PLC or a microcontroller?

The answer is easy - IT DEPENDS.

In general, it is much easier to build a machine using a PLC.
For a one off machine, a PLC easily wins.
For a small number of machines, a PLC easily wins.

If you are going into a production run of thousands+, then it may be that a micro controller is better.

If you want your machine/applcication to fit into a match box, a micro controller is the only way to go (for now...).

Remember, a lot of PLC's use micro-controllers for their CPUs and in their I/O, so using a PLC will not actually get you away from using a micro controller.

Doug

I think you will find PLCs preferred by customers and maintenance personnel since they have the ability to troubleshoot and repair problems, while not having the equipment available to diagnose a microcontroller device.

If your machine is a very unique idea it might be better for you financially to have a bunch of dependant customers, but if you are competing against other OEMs with similar equipment with reliability and downtime as important factors, the PLC controlled equipment will probably win out.

Way if

The way I would look at it if I were the customer, is if the equipment were from a large manufacturer with many outlets who could deal with repairs, then I would probably not need to know what or how it was controlled so the microcontroller could be used.

BUT if this was a piece of custom machinery from a small to medium sized manufacturer who are the only people who can understand the product, then I would be vary wary and it would have to be pretty special before I would accept a microcontroller.