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Calibration for zero point drift (Field Calibration)
The zero point of the electronic inclinometers used in the AMS can drift slightly over time. If you use absolute level
as your reference plane, you might want to calibrate for zero-point drift occasionally. You can perform this
calibration in your own facility by using the calibration routine built into the MultiView application. If you work
relative to a reference plane other than absolute level, zero point
drift won’t affect your measurements, and you
don’t need to perform this calibration
procedure. In the following procedure for calibrating the zero point of the
AMS, the software instructs you to place the leveling wafer on a flat, level surface. The software takes an
inclination reading, instructs you to rotate the leveling wafer in place 180 degrees, and then takes a second
reading. The two readings are used to set the new zero point. It is important that the center of the leveling wafer is
in the same position on the surface before and after you rotate the leveling wafer. Most surfaces are not perfectly
flat, so moving the leveling wafer while rotating it can affect the accuracy of the calibration. The procedure,
therefore, instructs you to place marks on the surface at four points around the outside edge of the leveling wafer.
You can use these marks to rotate the leveling wafer without moving it off center relative to the first calibration
reading.
To calibrate your AMS using MultiView:
Locate a surface large enough to hold the AMS and having the following
characteristics:
• Level to within about 1 degree.
• Stable enough to ensure
that the inclination of the surface does not change during the
procedure.
• Sufficiently smooth and flat that the inclination readings of the
AMS
don’t
change if you move the AMS slightly in any direction.
If the surface doesn’t meet these requirements, i
t might introduce an error in the
calibration results.
Caution
Performing a zero-point calibration improperly can actually cause the AMS to produce absolute level
readings that are less accurate than readings from the AMS prior to the zero-point calibration. This is likely
to be true if the surface used for the calibration is not sufficiently stable and flat. To remove a zero-point
field calibration, run the zero-point calibration procedure again and click
Reset to Factory Default
in the
first step of the procedure.
