METHOD OF AND APPARATUS FOR NONOBTRUSIVELY OBTAINING ON-LINEMEASUREMENTS OF A PROCESS CONTROL DEVICE PARAMETER

摘要

An apparatus for nonobtrusively determining one or more parameters, such as dead band, dead time, or response time of a process control device that is connected on-line in a process control loop includes a measurement unit and a processing unit (30). The measurement unit is coupled to the process control loop to detect stochastic changes in a control signal sent to the process control device and to detect an indication of the response of the process control device to the changes i n the control signal while the process control device is operating on-line. The processing unit calculates the device parameters from one or mo re sets of the detected changes in the control signal and the detected response indication.