| 摘要 |
PURPOSE:To realize an accurate control of tank level even when the continuous measurement is impossible for the tank level, by making use of control signals of control valves provided at the inlet and outlet of a tank to simulate the level change. CONSTITUTION:Controllers 22 and 8 apply the control signls to inlet and outlet valves 6 and 7 respectively to control so that the tank level l is coincident with a target level point A. At the same time, these control signals are supplied to an integration circuit 19. The circuit 19 integrates the difference between both control signals. Therefore the output ei of the circuit 19 increases as the level lrises up in accordance with the lapse of time. Thus it is possible to estimate the actual tank level by observing the output of the circuit 19. Furthermore the output of the circuit 19 for tank model can be corrected to the correct value by making use of the voltage signal at the passing point of a detector. |
