| 摘要 |
PURPOSE:Not only to remarkably reduce an integral dose in case when a process load has been varied suddenly, but also to shorten a setting time, by deriving a fluctuation ratio of the load, and initializing an integral term to an integral value corresponding to this ratio. CONSTITUTION:A control part 1 inputs a target value TUP and a process variable signal TWO, its deviation is made to pass through an integral operation control part 8, and VK, VTD and VTi are obtained as a result of operation. The result of operation is inputted to a selecting part 9 as TC1=VK+VTi+ VTD. Also, a deciding part 10 outputs a control signal Si to the integral operation control part 8 and the selecting part 9 in case when the TUP is not varied and the VTD has exceeded some first set value VS1. In accordance with the signal Si, the selecting part 9 selects a regular PID control output TC=TC1, or TC=TCmin in case when the Si signal has exceeded the negative side VS1 of the VTD, and TC=TCmax in case when the VTD has exceeded the positive side VS1, and controls the process part as an output of the control part. |
