| 摘要 |
PURPOSE:To previously prevent the occurrence of an accident at a plant, by switching the automatic operation mode to the manual operation mode for a subject of control in case when some fault is detected from the detection variation factor obtained by a monitor means. CONSTITUTION:This control system comprises a detecting part 31 that detects the process quantity from a subject of control, a controller 32 and an operation terminal 40 that converts the output given from the controller 32 into the operation quantity and influences the subject of control. An input arithmetic part 33 is provided to the controller 32, and the arithmetic output is applied to a control part 35 to perform a PID operation. The result of this operation is applied to the terminal 40 via an automatic-manual changeover part 36. In addition, an arithmetic part 38 a PV variation factor is provided to the controller 32 to calculate the variation factor of the PV value. A monitor switch 39 functions when the output of the part 38 exceeds a prescribed level and drives the part 36 to change the automatic operation mode to the manual operation mode. |
