Level Field Check for the Laser Tracker

1. Glue 2 nests on the ground about 17ft apart. (The distance represents approximately 0.001" over one arcsecond of angle. Since we expect the level to be accurate to approximately +/- 2 arcseconds, this will equate to +/- 0.002" inches in the final analysis)
2. Ensure the Tracker is properly warmed up and the mounting is stable, and level enough to use the Measure>Level command. Also, the atmosphere out to 20 ft should repeat to +/-0.001" (This can be checked by running a Static Test in the Operational Checks, to see if the Tracker is level enough, use the Bubble Level on Tracker Pad. The bubble should be well centered in the center ring)
3. Measure Level with the Tracker M_LEVEL001
4. Measure the 1^st point on the floor as a Comp Off point (2000-3000 samples per measurement) M_POINT001
5. Measure the 2^nd point on the floor as a Comp Off point (2000-3000 samples per measurement) M_POINT002
6. Construct a 3-2-1 coordinate system. Plane-Level, Line-Pt1 to Pt 2, Origin-Pt1 C_COORDSYS001
7. Note the Z height of Pt2
8. Place a shim under one of the tripod feet. (shim should be approximately 0.250"… you can use the shim from the tooling kit)
9. Check to make sure the Tracker is still level enough (Again, use the Bubble level. This time, the bubble will have drifted a bit, but it still needs to be green in color, and inside the middle ring)
10. Re-measure Level with the Tracker M_LEVEL002
11. Re-measure the 1^st point on the floor as a Comp Off point (2000-3000 samples per measurement) M_POINT003
12. Re-measure the 2^nd point on the floor as a Comp Off point (2000-3000 samples per measurement) M_POINT004
13. Construct a 3-2-1 coordinate system. Plane-Level, Line-Pt3 to Pt 4, Origin-Pt3 C_COORDSYS002
14. Note the Z height of Pt4
15. Compare the Z height of Pt4 when C_COORDSYS002 is active to the Z height of Pt2 when C_COORDSYS001 is active. These numbers should be within 0.004" of each other when all other conditions are met (atmospheric, etc…)

Note: the reason the 2 values cannot be compared in the same coordinate system is because the device position moves during the shimming operation, meaning the Z height from Coordinate System 1 is only valid when that is the active coordinate system.

Note:  These instructions were written using CAM2 Measure X, but they can be adapted to any other software.

Keywords:

level, accuracy, repeatability, faro laser tracker