Attached here is Mono compatible BasicTrendChart control based on ZedGraph (licensed under LGPL-2.1 which is attached).
Do read the comments inside the class since it requires the ZedGraph.dll to work.
It is intended to be used as Value/Time graph.
The X Axis is set for Auto Scaling.
PLCAddressValue can be shown in the Series Title (see the picture). Just set the GraphSeriesTitleIncludeAddress property to True.
Special Notes:
* Mono Environment - All mouse interactions with the graph are disabled since the app could crash.
* Windows Environment - Additional feature: Double-clicking the graph will start/stop its updating with new points.
* General - setting the Y-axis Max or Min values will prevent the axis from auto scaling so the graph will get cut off if it goes above/below those points.