29
11. CHECKS AND ADJUSTMENTS
A DT is a precision instrument that requires fine adjustments. It must be inspected
and adjusted before use so that it always performs accurate measurements.
• Always perform checking and adjustment in the proper sequence beginning
from "11.1 Plate Level" to "11.4 Optical Plummet".
• In addition, the instrument should be inspected with special care after it has
been stored a long time, transported, or when it may have been damaged by a
strong shock.
• Make sure the instrument is securely set up and stable before performing
checks and adjustments.
The bubble tube is made of glass, so it is sensitive to temperature changes or to
shock. Check and adjust it as outlined below.
X
PROCEDURE Checking and adjusting
1. Level the instrument and check the
position of the bubble in the plate
level.
C
"5.2 Leveling", steps 3 to 5.
2. Turn the upper part through 180
°
and
check the bubble position.
If the bubble is still centered, no
adjustment is necessary.
If the bubble is off-center, adjust as
follows.
3. Correct half of the bubble
displacement using leveling foot screw
C.
11.1
Plate Level