| 摘要 |
PURPOSE:To prevent an unnecessary air compressor from being put into operation, by beginning to operate a necessary number of air compressors as a stop instruction is cut off before the load sharply increases, and by thereafter applying the stop instruction again when the load pressure has dropped. CONSTITUTION:When a time point T-t is reached, a pressure drop signal is forcibly applied to compressors by a predicted operation start instruction, regardless of the load pressure, so that a necessary number of compressors are run for a time t. In that case, a pressure rise signal HC is forcibly withheld. After a time point T, the quantity of air being used by the load increases sharply so that the load pressure becomes lower than a pressure rise point H. For this reason, a compressor stop instruction being cut off after the predicted starting of the compressors is applied again so that an original controlled state is restored. |
