-
Reading the wrong vernier scale
-
Misreading the vernier
There are two sets of vernier scales marked on a single vernier. While taking reading, use that set of figures which increase in the same direction as the figure in the main direction.
-
Reading the vernier in the wrong direction.
-
Turning the wrong tangent screws
-
Failing to tighten the clamp screw.
-
Reading the numbers on the horizontal scale from the wrong row.
-
Reading angles in the wrong direction.
-
Sighting on the wrong signals or setting up over the wrong station
-
Booking the wrong values
-
Missing the wrong right or left in deflection angle
-
Using haphazard field procedure.