Abstract: A process control apparatus is provided which has a PID controller to which is supplied a sampled signal of a control deviation signal of a process value signal and a reference signal and which generates a PID control signal according to sampled-value PID control constants. A non-linear controller is connected in parallel with the PID controller. A sum signal of the output signals from the PID controller and the non-linear controller is supplied to a process through a holding circuit. The process control apparatus further includes a circuit for identifying the dynamic characteristic of the process according to the sum signal and the sampled signal of the process value, and a circuit for calculating a transfer function of the process in the Laplace operator domain and for determining the sampled-value PID constants of the PID controller according to the dynamic characteristic.

Abstract: A process control apparatus capable of adjusting control constants of a process control operation which controls a controlled process. The process control apparatus includes an identification signal generator for producing a maximum length sequence signal, an adder for adding this maximum length sequence signal and a control signal and supplying it as an operation signal to a process, an operation circuit for identifying the pulse transfer function of a process response from the process signal and the operation signal and processing the transfer function by Laplace-transforming the step response of the pulse transfer function, and a circuit for processing control constants according to the transfer function.