Defines the size of OPC Block's set of values. Please check Driver's documentation for information about the limit for this property, according to B1 to B4 parameters. By creating Elements for the OPC Block, it allows both accessing the values read and also allows writing values to the device. Default value of this property is 0 (zero). Example:

Sub OPCBlock1_OnStartRunning()
  Size = 12
End Sub