Process controller design with process approximation and lambda tuning

A system for tuning a proportional-integral-derivative (PID) process controller for use in controlling a process when the PID process controller is connected to the process via an input/output network, the PID process controller, the input/output network and the process forming a process loop, comprising:

• a first computer implemented software component that determines, via a computer processor, one or more characteristics of the PID process controller, including an execution rate of the PID process controller;
• a second computer implemented software component that determines, via a computer processor, one or more characteristics of the process, including determining a plurality of time constants of the process and a plurality of dead times of the process;
• a third computer implemented software component that determines, via a computer processor, one or more characteristics of one or more devices within the input/output network of the process loop, including determining at least one of one or more input/output device scan rates and one or more input/output time constants and one or more input/output dead times associated with the one or more devices within the input/output network of the process loop;
• a fourth computer implemented software component that calculates, via a computer processor, an estimate of the process loop, by determining first and second order time constants of the estimated process loop as a function of the plurality of process time constants and the one or more input/output time constants and by determining a dead time of the estimated process loop as a function of a summation of the plurality of process time constants and the one or more input/output time constants and the one or more input/output device scan rates and the execution rate of the PID process controller and the one or more input/output dead times and the plurality of process dead times;
• a fifth computer implemented software component that determines, via a computer processor, a set of PID process controller tuning factors from the estimated process loop time constants and the estimated process loop dead time;
• and
• a sixth computer implemented software component that provides the PID controller with the determined set of PID process controller tuning factors for use by the PID controller during operation of a process.

A process control system for controlling a portion of a process using a process control loop, comprising:

• a proportional-integral-derivative (PID) process controller;
• a plurality of input/output communication devices connected between the PID process controller and the process to measure one or more process variables and to communicate the measured process variables to the PID process controller and to send one or more control signals from the PID process controller to a controlled device in the process;
• and
• a process controller tuner, including;
• a processor,
• a process controller tuning routine stored on a memory and adapted to be executed on the processor to,
• (1) estimate the process control loop as a second order plus dead time process by;
• (a) determining first and second order time constants of the estimated process control loop as a function of a plurality of process time constants associated with the operation of the process and one or more input/output time constants associated with the operation of one or more of the input/output communication devices, and
• (b) determining the dead time of the estimated process control loop as a function of a summation of the plurality of process time constants and the one or more input/output time constants and one or more input/output device scan rates and the execution rate of the PID process controller and a plurality of process dead times and one or more input/output device dead times associated with one or more of the input/output devices;
• and
• (2) determine a set of PID process controller tuning factors from the first and second estimated process control loop time constants and the estimated process control loop dead time.