Operation - David White L6-20 Owner's Manual

Initial Operation
!
WARNING
direct sun light.
Do not subject the instrument to extreme
temperatures or variations in temperature.
As an example, do not leave it in vehicles
for long time. In case of large variations
in temperature, allow the measuring tool
to adjust to the ambient temperature
before putting it into operation. In case
of extreme temperatures or variations
in temperature, the accuracy of the
measuring tool can be impaired.
Avoid heavy impact or falling of the
instrument. After heavy exterior impact on
the instrument, an accuracy check should
always be carried out before continuing
to work.
Setting Up Instrument
!
WARNING
Make sure that the tripod points are well
into the ground. On paved surfaces, be
sure the points hold securely.
The legs should have about a 3-1⁄2 foot
spread, positioned so the top of the tripod
head appears level.
If using a tripod with adjustable legs, be
sure the leg clamps are securely hand
tightened.
Before setting up your instrument, be sure
clamps are loosened and telescope lock
lever 9 (LT6-900) is in the closed position.
Attach the instrument to the tripod
securely, hand tightening the instrument
base to the 5/8-11 tripod head.
Setting Up Over a Point
!
WARNING
All moving parts will turn freely and easily
by hand.
Hang the plumb bob, attach cord to the
plumb bob hook of the tripod.

OPERATION

Protect the instrument
against moisture and
It is important that the
tripod is set up firmly.
Never use force on any
parts of the instrument.
Move the tripod and instrument over the
approximate point. (Be sure the tripod
is set up firmly again. Loosen leveling
screws and shift the instrument laterally
until the instrument is positioned directly
over the point.
If necessary, the instrument can be
shifted by loosening the tripod center stud
and sliding the instrument from side to
side for proper positioning.
Leveling the Instrument
Set the instrument leveling screws.
Turn down the leveling screws until firm
contact is made with the instrument base.
!
CAUTION
very possible to overtighten the leveling
screws. Only a firm contact between the
screws and the base is necessary. If the
instrument shifts on the base, turn down
the screw more firmly by hand.
Leveling the instrument so the vial bubble
remains centered through a 360° rotation
of the telescope is the most important
operation in preparing to use your
instrument.
When leveling your instrument, be sure
not to touch the tripod. Follow these
instructions carefully.
Again, be sure telescope lock lever 9
(LT6-900) is in the closed position.
Line up the telescope so that it is directly
over a pair of leveling screws.
Grasp these two leveling screws (A and
B) with the thumb and forefinger of each
hand.
-7-
Do not overtighten the
leveling screws. It is