120
TC605/TC805/TC905/L-1.1.1en
© Leica
Optical plummet
Check the optical plummet of the tribrach at regular
intervals. Any deviation of the line-of-sight from the
vertical axis of the instrument causes a centering error.
Checking by plumb-bob:
Set up and level up the instrument (with plumb-bob) on
the tripod. Mark the ground point. Remove the plumb-
bob. Check that the crosshairs of the optical plummet
intersect at the ground point. The accuracy achievable is
about 1mm.
605Z37
