GPI GPR-G9, Instruction Manual

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(2) After switching on the power, use the laser detector measuring the h1 of
X1-beam on the wall or scale plate.
(3) Loose the screw of the tripod, and then turn around the instrument 180° to
measure the h2 of X2-beam on the wall or scale plate.
D-value between h1 and h2 ought to be less than 10mm
(4) Check the Y-beam in the same way.
4.2 Horizontal-line Checking
(1) Place the instrument between two walls with the distance of 30m (or two scale
plates with the distance of 30m)
(2) Place the instrument according to horizontal setting and then adjust the
instrument.