Vertical 0 Point Error; Laser Plummet; Offset Constant - Pentax R-2501NS Instruction Manual

11.5 Vertical 0 point error

Make sure to follow check procedures mentioned below after making adjustments on reticle
and perpendicularity of line of sight to horizontal axis.
[Checks]
① Set up the instrument and turn the power on.
② Sight the telescope at any reference target A at Normal state. Read the vertical angle (y).
③ Turn the telescope and rotate the alidade. Sight the same target A again at Back state and
read the vertical angle R.
If y+R = 360° , no further adjustment is necessary.
[Adjustments]
If the deviation d (y+ R - 360° ) is wide, contact your local dealer.

11.6 Laser plummet

[Checks]
① Set the instrument on the tripod, and place a piece of white
paper with a cross drawn on it right under the instrument.
② Press the [LASER] key, and move the paper so that the
intersecting point of the cross comes to the centre of the
laser mark.
③ Rotate the instrument around the vertical axis, and observe
the centre mark position against the intersecting point of
the cross at each 90° rotation.
④ If the laser mark always coincides with the intersecting
point, no adjustment is necessary.
[Adjustments]
When a centre part where a cross intersection and the laser
mark look the brightest shifts by 0.5mm 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.

11.7 Offset constant

The offset constant rarely changes. It is recommended, however, that checks 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.
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