Checking Automatic Level Accuracy - GOL 32 D
How accurate and precise
is your level? here are tests to verify if your level needs calibration or
Circular bubble test:
your instrument on a tripod in an area that is as level as possible.
your circular bubble using the tripod legs or the three-foot screws.
the instrument 180⁰ to see if the bubble remains centered, if it remains
centered then the instrument is in good condition but if it does not the
instrument will require calibration by a competent and qualified engineer
Two peg test:
up the instrument
in an area that is as level as possible and which is about 220 feet long. Place
two matching level rods or two pieces of strapping in the ground about 200 feet
apart with the faces toward each other. Position and level the instrument so
that the distance from the instrument to each rod is the same measure.
a reading on each rod with the instrument (or mark each piece of strapping
where the cross-hair is sighted).
transit to another spot on the line and take readings and mark both rods again.
difference between the marks on the rod will be the error of the instrument.