From OpenSCADAWiki
Users have an ability to change the PID-regulator's coefficients, mode, set-point, output and immediately to see the reaction on the diagram. In addition, the user may learn the history of the regulator work, which requires the left mouse button click in the graph area and by means of appeared trend's control panel to make the necessary navigation actions. To return the control panel of the parameter the left mouse button must be clicked in an empty area of the frame.