Specifies this Element's position among the other Elements configured by the I/O Block's Size property where it is inserted. This property accepts values between 0 (zero) and a value less than the value defined in the Size property. For example, when configuring an I/O Block to set Size to 20, the maximum valid number for the Index property is 19 and the minimum valid number is 0 (zero), but when mapping Elements of a Block, E3 Studio automatically adjusts the Index property to the value specified. Example:

Sub Element_OnStartRunning()
  Index = 15
End Sub