Topcon GPT-2003 Manuel d'utilisateur télécharger pdf (Page 144)

17 CHECK AND ADJUSTMENT

17-8

17.3.5Checking / Adjusting the Optical Plummet Telescope

Adjustment is required to make the line of sight of the optical plummet telescope coincide with the

vertical axis ( otherwise the vertical axis will not be in the true vertical when the instrument is optically

plumbed).

● Check

1) Coincide the center mark and the point. (See Chapter 2 “PREPARATION FOR MEASUREMENT”.)

2) Rotate the instrument 180° or 200g around the vertical axis and check the center mark.

If the point is properly centered in the center mark, adjustment is not required. Otherwise, adjust in

the following manner.

● Adjustment

1) Take off the adjustment section cover of the optical plummet telescope eyepiece. This will expose

four capstan adjustment screws which should be adjusted with the accessory adjusting pin to shift

the center mark to the point. However, correct only one-half of the displacement in this manner.

2) Use the leveling screws and coincide the point and center mark.

3) Rotate the instrument 180° or 200g around the vertical axis once more and check the center mark.

If it is coincided to the point, then further adjustment is not required. Otherwise, repeat the

adjustment.

Note: 1 First, loosen the capstan adjustment screw on the side to which the vertical cross-hair

line must be moved. Then tighten the adjustment screw on the opposite side by an equal

amount which will leave the tension of the adjustment screws unchanged.

Revolve in the counterclockwise direction to loosen and in the clockwise direction to

tighten, but revolve as little as possible.

2Perform following adjustment after completing above adjustment . Section 17.3.7

“Adjustment of Vertical Angle 0 Datum”, Section 17.2 “Checking the Optical Axis”.

Note: First, loosen the capstan adjustment screw on the side to which the center mark must be

moved. Then tighten the adjustment screw on the opposite side by an equal amount which

will leave the tension of the adjustment screws unchanged.

Revolve in the counterclockwise direction to loosen and in the clockwise direction to tighten,

but revolve as little as possible.

Capstan

adjustment

screws

Eyepiece

Capstan

adjustment

screws

Plummet telescope

Half amount of

displacement

Total amount of

displacement

1 2 ... 139 140 141 142 143 144 145 146 147 148 149 ... 167 168

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Topcon GPT-2003 Manuel d'utilisateur Page 144