Determines the number of points kept on a Realtime-type of Pen. After this value, older data is discarded. This property is only considered after connecting a Pen. For more information, please check the Connect method. Default value of this property is 1000, and it must be always greater than 0 (zero). Example:

Sub CommandButton1_Click()
  Set Pen1 = Screen.Item("E3Chart1").Pens.Item("Pen1")
  Pen1.Disconnect()
  Pen1.BufferSize = 5000
  Pen1.Connect()
End Sub