Johnson Level & Tool Mfg. 40-6935 - Manual (Page 26)

26 ©2011 Johnson Level & Tool
Perpendicular Degree of The Visual Axis and The Horizontal Axis
Checking
• Set two targets as high as the instrument, one in front of and the
other behind the instrument, each about 50 meters away from the
instrument. Level the instrument precisely and power it on.
• Aim at target A with crosshair of the telescope in plate-leftward
position.
• Rotate the telescope around the horizontal axis 180º to aim it in
the opposite direction.
• Aim at target B which is the same distance to target A.
• Rotate the instrument 180°. Aim at the target A, then lock the
horizontal clamp.
• Rotate the telescope 180º around the horizontal axis again. Aim at
the target C. Target C should be the same with target B.
• If not coincident, adjustment is necessary.
4430H-English_Manuals 2/22/11 11:08 AM Page 26