| 摘要 |
PURPOSE:To raise the efficiency of operation, by holding an operating instruction by a stepping relay capable of freely selecting the pump operating sequence after making distinction between a large pump and a small pump when an instruction for decreasing the number of operative pumps is outputted. CONSTITUTION:When a condition that a flow-rate setting signal is greater than a guasi-discharge rate is satisfied, an alarm setter 15A produces a pump increasing signal 16 for shifting a stepping relay 18 for a normal direction. On the other hand, when the following relationship, (flow-rate setting signal) - (discharge rate of a small-capacity pump) = (guase-discharge rate), is satisfied, an instruction 17A for decreasing the speed of the small capacity pump is outputted. Similarly, when the following relationship, (flow-rate setting signal) - (discharge rate of a large-capacity pump) = (guasi-discharge rate), is satisfied, an instruction 17B for decreasing the speed of the large-capacity pump is outputted. These pump speed decreasing instructions are applied to the stepping relay 18 after passing through a contact 24 for making distinction between the small-capacity and the large-capacity pumps to be started finally, and then cause shifting of the stepping relay 18 in a negative direction. |
