Wow, any help may be appreciated but you have not given much information to get much help. Rate implies that an amount of stuff is moved over some unit of time. I.E. Feet/minute, Gallons/hour, Cu.Ft./Second, etc. Now, what method of measuring your "stuff" do you have and if you find that out, programming in PLC3 or any other system will doubtless turn out close to the same. The PLC3 is a very old system but the rules do not change because of it. You have to know certain information about your system and to get any help here, the more information you supply, the better the reply. This is about as good as I can do with what you have said so far.