| 摘要 |
PURPOSE:To attain stable and proper control even if the number of running units is changed by changing a parameter to be applied to a control operation block in accordance with the number of running units out of apparatuses to be controlled through a parameter changing operation block. CONSTITUTION:In a process control device, its control operation block 3 finds out a control output signal R on the basis of a deviation (e) between an objective value P and a flow rate signal Q outputted from a flow rate detector 1 and sends the signal R to output signal grade limiting blocks 4. These blocks 4 output 0% control output signals R1-Rn at the stop of pumps 2 and control output signals R1-Rn corresponding to the difference between bumpless signals U1-Un and the control output signal R at the operating status of the pumps 2 to apply the signals R1-Rn for driving motors of the pumps 2. The parameter changing operation block 5 calculates a proportional band to be applied to the block 3 so that the proportional band is automatically compensated in accordance with the number of running pumps 2. As the result of the compensation, an open-loop transmission function of the whole control system is stabilized without variation even if the number of running units is changed. |
