Hi,
While attempting a vertical axis adjustment on a Nikon DTM-322, the result screen indicated:?ÿ Tilt:?ÿ -1", ACV: Over and ACH: 11"
The manual identifies ACV as Altitude Constant Adjustment and ACH as Sighting Axis Error.
Could anyone explain what these three items are and what to do if any are reported out of range (or Over)?
thanks,
Phil
Those three items are the adjustments that are being applied to raw measurements from the instrument, based upon the field adjustment procedures - typically multiple measurements in both faces.?ÿ
The tilt error (also called trunnion axis error) is applied to bring the horizontal (tilting) axis of the instrument perpendicular to the plumb line. Altitude constant adjustment is applied to offset collimation error in the vertical circle, and sighting axis error adjustment will align the axis of the sighting scope to be perpendicular to the tilting axis.
Most (all) total stations will drift a bit over time, which is why you want to perform the check & adjust routines regularly.
Each instrument has a set limit for these internal adjustments, and once any of them are over that limit (out of range) it is time to send the instrument to your local service shop for calibration.
It appears your instrument has surpassed the maximum internal adjustment limit for the ACV - it is time to get it checked out by a service tech.