A PID tuning tool for networked control systems This paper presents a software tool that can be used for PID controller tuning in networked control systems. The problem with networks, when control issues are considered, is that they cause varying delays in the measurements. A delay in the feedback loop may cause instability and it thus complicates control design, and a varying delay makes the design task even more difficult. The PID tuning procedure that is implemented in the tool is based on simulation and constrained optimization techniques. First, the control system is modeled, and then its performance is optimized with respect to a cost criterion. The networks are modeled with delay distributions in the control system simulation model. The tool provides an easy-to-use graphical user interface for tuning PID controllers manually or automatically.