Does anyone know what the circles (boxed in red) mean?
My understanding of the Xs are inf shutdowns/connectivity issues from plc to interface, etc... Just don't understand what the circles are.
Those circles are colorblind markers. In the legend it denotes the markers used by each trace, so the first trace is using a solid green circle while the second is using an empty blue circle. Colorblind markers exist by default on all trends:
By default a trend also includes color-blind markers to differentiate traces on monochrome screens. Color-blind markers are evenly spaced along a trace and do not indicate archived data points.
Retrieving data ...