| 摘要 |
PURPOSE:To reduce the change of an average flow rate by obtaining an focusing direction signal of the deviation which is produced according to whether the deviation between a liquid level detecting signal for fluid container and a liquid level setting signal is larger or smaller than zero out of a blind sector area and obtaining a flow rate set value signal from said focusing direction signal. CONSTITUTION:A comparison/decision parts 171 and 172 receive the effective deviation signal C delivered from a control signal output means 14 with blind sector area and detect that a control deviation signal B exceeds the blind sector area. The part 172 discriminates whether or not the level of a tank 11 is lower than the set value of a setting part 141 and the signal B is set in the positive direction beyond the blind sector area. A focusing direction signal F is obtained from an addition arithmetic element 202. While the part 171 discriminates whether or not the level of the tank 11 is higher than the set value of a level setting part 141 and the signal B is set in the negative direction. Then the part 171 delivers the signal F to increase the set value of a flow rate controller 22. When the level of the tank 11 exceeds the upper limit of the blind sector area, an input flow rate (memory output fM + set value alpha) is fixed. Then an input flow rate (fM-alpha) is set when the tank level exceeds the lower limit of the blind sector area. Thus the level of the tank 11 is set in the focusing direction. |
