摘要：In this paper a trial has been m.de to design a sim.le self-tuning LabVIEW-based PID controller. The controller uses an open-loop relay test, calculates the tuned param.ters in an open loop m.de of operation before it updates controller param.ters and runs the process as a closed-loop system. The controller reacts on a persistent offset error value as a result of load disturbance or a set point change. Practical results show that such a controller m.y be recom.ended to control a variety of industrial processes. A GUI was developed to facilitate control-m.de selection, the setting of controller param.ters, and the display of control system.variables. GUI m.kes it possible to put the controller in m.nual or self-tuning m.de.