Research on the Dynamic Characteristics of a Real Process Control System

This investigation forms a part of the research on the optimum conditions in the process control. In this paper, using a real process whose scale of plant is the same as actual one, the dynamic characteristics of the comprising elements in the process control system and the cotrolling performance of the whole system are investigated analytically and experimentally. The results obtained from this research may be summarised as follows: (1) The dynamic characteristics of air compressor, reduction gearing, VS-motor, etc. are clarified analytically. (2) The polytropic constant of the air vessel and the coefficient of discharge at the flow-out valve are decided not only analytically but experimentally. (3) It is shown that, in such a non-linear system as this process control system, it is meaningless to analyse the system quantitatively without confirming the correspondency of several characteristic values in the system. (4) It is clarified that such cascaded control system as this system, consisting of a VS-motor and a pneumatic controller, gives an excellent control performance for the control of the gas process.