It is not so difficult to design a fully automatic control system for the chemical plant, if control engineers and instrumentation engineers understand the static and dynamic characteristics of that plant. However the behavior of those plants specially so-called bio-plants is not easily measured and understood. If a plant in an organization does not perform a vital role or dose not require very accurate control, a relatively simple control system, i.e. only to maintain the plant at its current state or prevent it from moving into abnormal states, may be sufficient from point of view of reducing the operative personnel. The aim of this study is to establish the effectiveness of the autonomous control system for such a situation.