Leica LS10 - Guidelines for Special Measurement Situations

Taking a precision measurement
• Limit the target distance to ≤ 30 m.
•
Ensure a minimum ground clearance of 0.5 m to minimise the inuence of
refractions due to ground proximity.
•
Apply double observation methods, such as BFFB or aBFFB, to increase the
reliability of the measurement and to reduce possible errors caused by the
staff sinking.
•
Apply alternating observation methods (aBFFB = BFFB FBBF) to eliminate
the horizontal tilt. The horizontal tilt is the residual error of the automatic
compensator.
•
When taking measurements near the edge of the levelling staff, the
reduced number of staff code elements may slightly lower the measuring
accuracy. To maintain highest accuracy, activate the precision mode in
the tolerance settings of the LineLevel program. When activated, the
instrument monitors whether the height reading is within 0.50 m to either
end of the staff (top and bottom). The top and bottom limits of the staff
are automatically converted to a 3 m Invar staff. In order to use different
staff sizes, you can manually adjust the limit values.
The precision mode also monitors critical distances between the instru-
ment and the staff. These distances depend on the physical properties of
the staff code. The measuring accuracy of height measurements within
these distance ranges may also be slightly lower. A warning is displayed if
the measuring distance is within the following ranges: 13.250 m -
13.500 m and 26.650 m - 26.900 m. If the instrument detects a staff dis-
tance within these ranges, slightly move the staff out of the mentioned
measurement range in order to maintain highest measurement accuracy
expectations.
Visual control of the levelling staff
When looking through the telescope, e.g. for visual control while taking a
measurement, a low intensity red blinking LED light may be visible, especially
when measuring in low light surrounding. This LED light is used in the illumina-
tion of the compensator and has no impact on the eye safety of the user.
5.2 Guidelines for Special Measurement Situations
Vibrations
Touch the upper third of the tripod to reduce the vibrations at the instrument,
for example caused by wind.
Back light
Low sunlight may inuence the ability of the instrument to read the levelling
staff. Use the sunshade delivered with the instrument to shield the objective.
Darkness
When working in darkness (for example tunnelling), evenly illuminate the
measuring area of the levelling staff with a ashlight or a spotlight or use a
special self-illuminated staff (for example Nedo Lumiscale).
Measuring at the lower end of the levelling staff
Measurements slightly below the zero point of a staff are possible and will
result in negative measurement values.
Special measurement
situations
32 Measurement Guidelines