| 摘要 |
PURPOSE:To prevent incovenience to a process due to a rapid restoration not suitable to a process state when a variable to be controlled out of a pattern control of the variable to be controlled is restored. CONSTITUTION:In case of the temperature control of a furnace, an analog input section 1 inputs the measuring value of an analog furnace temperature as a variable to be controlled PV, converts the value into a digital quantity and inputs to an operation section 2. A memory 3 is stored with a program pattern designated to a set value to control the furnace temperature in response to time in addition to a program data representing the operation procedure. If the control is interrupted by a power failure and the pattern control is restarted, an optimum rate of change for the restoration of the dropped furnace temperature to an objective set value is selected from the memory 3, and the program pattern designating the set value increasing with the optimum rate of change from a variable to be controlled PV1 at that time to an objective SP1 such as line A is generated at the operation of the operation section 2 and this is given to a control section 4 for manipulated variable. Based on this signal, a manipulated variable MV is outputted to a furnace temperature control section. |
