Try to use this one instead:
For Each b in WorkSheets("Device").Range("B10:B20").Cells
Set pt = srv.PIPoints(b.Value)
b.Offset(,1).Value = pt.PointAttributes.Item("descriptor")
Next
where b.Offset(,1)
gives you cell one column to the right from b
, i.e. if b
points to B11
then b.Offset(,1)
points to C11