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 in the control signal while the process control device is operating on-line. The processing unit calculates the device parameters from one or more sets of the detected changes in the control signal and the detected response indication.