You will want to offer more information than that.
Are you looking to automate existing machines and generate OEE information or are you looking to tap into an already automated machine and obtain OEE?
Your question may appear simple, but how you get there requires additional questions, first determining what you have and then determining what you want to know.
I've been calculating it, displaying it on the HMI and the customer(s) have been satisfied (each has their own little twists). Some will drop a network connection and poll it for their reports, etc.