Laser Plummet; Offset Constant - Pentax W-800 Series Basic Instruction Manual

4.6 Laser plummet

[Checks]
Set the instrument on the tripod, and place a piece of white paper with a cross drawn on
it right under the instrument.
Press the [LASER] key, and move the paper so that the intersecting point of the cross
comes to the center of the Laser mark.
Rotate the instrument around the vertical axis, and observe the center mark position
against the intersecting point of the cross at each 90° rotation.
If the Laser mark always coincides with the intersecting point, no adjustment is necessary.
[Adjustments]
When a center part where a cross intersection and the laser mark look the brightest shifts by
0.8 mm or more (at the instrument height 1.5m), it is necessary to adjust it. A repair engineer
does this adjustment. Please contact the PENTAX dealer.

4.7 Offset constant

The offset constant rarely changes. It is recommended, however, that check be done once or
twice a year. The check of the offset constant can be done on a certified base line. It can also be
obtained in a simple way as described below.
[Checks]
1. Locate points A, B and C at about 50m intervals on even ground.
2. Set up the instrument at point A, and measure the distances between AB and AC.
3. Set up the instrument at point B, and measure the distance BC.
4. Obtain the offset constant (K):
K = AC - (AB+BC)
[Adjustments]
• Contact your local dealer for adjustment of the off-set constant when the K is not nearly 0.
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