Abstract: A plurality of proportional plus integral plus derivative ("PID") parameters are prestored in a memory device and at the leading points of respective time segments of a program pattern, PID parameters adequate for the time segment are read out and PID control actions are made by utilizing read out parameters for effecting a process control.

Abstract: A method and apparatus for process control of batch processes utilizing the steps of storing in a memory the actual measured values of the process variable and utilizing the memorized values for an estimative operation to determine the timing for supplying a manipulated variable to the process. Thus, the process control apparatus of the present invention commits to memory the actual measured values of the process variable, utilizes the memorized values for the estimative operation to determine the point of time for suspending the supply of the manipulated variable and the point of time for starting the regular constant value control and, based on the outcome of this estimative operation, effects the separation of the process control under the steady condition from the control under the transient condition. Such a control operation ensures that the control value is not increased beyond its limit and, at the same time, it permits the adjusting period to be reduced to the minimum.