23. SETTING THE INSTRUMENT CONSTANT
The instrument constant will affect the accuracy of measurement result; therefore
setting of these should be performed with special care. This should be done by a
properly trained service technician.
23.1 Tilt zero point error check and adjustment
If tilt angle compensation has been selected, the tilt zero point error will adversely
affect vertical angle measurement. So it is necessary to check and adjust the tilt zero
point error periodically.
23.1.1 Checking zero point error
1.
Carefully level the instrument. Press
【
SFT
】，
and then press
【
*
】
to come in
the star function mode.
2.
Sight the target, then press
【
TILT
】
to display the tilt angle in the X (sighting)
direction. Wait for the display to stabilize, then read the tilt angle value t1.
3.
Rotate the top of the instrument through 180°and sight the same target again.
Wait for the display to stabilize, then read the tilt angle value t2.
4.
Calculate the offset value (tilt point zero error).
Tilt offset =
（
t1+t2
）
/2
If the offset value falls within the range ±20
″
, adjustment is not necessary. Or
adjust the value using the following procedure.
23.1.2 Tilt zero point error adjustment
Operating
Keys
Display
1
．
Level instrument carefully, then turn the
power on. When the message to prompt
setting vertical angle to 0 is displayed, press
【
3
】
and hold on
，
while rotating the
telescope at the same time until the screen
of inputting password is viewed.
【3】
Instr.ADJ
Password：
【
】
2
．
Input “1234”
，
then press
【
】
to come
in <Instr. ADJ> menu.
Instr. ADJ
1．Tilt offset
2．V0 & Coll.Crn
3．Instr.Const
95
Summary of Contents for CST202
Page 1: ...CST202 CST205 INSTRUCTION MANUAL Electronic Total Station...
Page 117: ......
