Fuzzy logic provides programmable logic controllers (PLCs) with the ability to make "reasoned" decisions about the process, thereby allowing them to make autonomous output calculations based on system inputs. Fuzzy logic systems use a three-step process fuzzification, fuzzy processing and defuzzification - to evaluate system parameters. In fuzzification, the system translates inputs into sets of data defined by membership functions and labels. During fuzzy processing, the system analyzes the input sets by comparing them against a set of predetermined rules. During defuzzification, the system translates the fuzzy processing data into a control system output. Thus,by using this three step process, a PLC with fuzzy logic capabilities can judiciously determined the proper control response to system inputs based on predefined criteria.