This property selects the number of series to be made visible in a graph. When this property is set to a value greater than zero, you may use the ScrollOffsetSeries property to define the first series to be made visible.
value = getViewableSeries();
Is any integer between 0 and the number of series in the data that defines the graph. 0 (show all series) is the default value.
Note: The setDataRange() method can also be used to set the number of series to be made visible in a graph. It establishes the range of data that is used in a graph.
See ScrollOffsetSeries, ViewableGroups, ViewableSeriesStock,setDataRange().