Welcome to PF, Mahmoud. Can you be a little more specific so that we can help you? By PLC, I'd assume you mean programmable logic controller. But there are many kinds of PLCs, many applications, and many purposes for various kinds of simulations you might want to run.
Can you provide some web links to the kinds of PLCs that you have in mind? And maybe a link or two from a google search on PLC simulators that shows us what you are looking for?