Kingview has real-time curves, but no historical curves. Call the historical trend curve control, which is very powerful and simple to use. Through this control, you can not only draw the curve of Kingview historical data, but also draw the curve of historical data in industrial library and data recorded in ODBC database. Moreover, in the running state, you can dynamically add/delete curves, infinitely zoom curves and charts, dynamically compare curves, print curves and so on.