Code:
If PortB.0 = 1 Then 'monitor PortE.2 for beam break
   DataIn2 = DataIn2<<1 'Move bit one place to left to concatinate variable
   DataIn2 = DataIn2 + 1 'something blocking beam, write a 1 to DataIn2 variable
Else 
   DataIn2 = DataIn2<<1
   DataIn2 = DataIn2 + 0 'Beam clear, write a 0 to DataIn2 variable
EndIf
How about doing it this way?