Andrew ES76PK-1 installation instructions Installation Procedures, Centering

Relocate stick to rib #7. Rotate theodolite, focus and adjust elevation to the scribe line and record this reading as R2.

Relocate stick to rib #10. Rotate theodolite, focus and adjust elevation to the scribe line and record this reading as R3.

Calculate an average angle by adding R1, R2, & R3 together and dividing by 3. Record this as R4.

Adjust theodolite elevation angle to this new angle R4.

Adjust the tribrach leveling screw #1 (nearest the alignment stick, which should be in rib #10, see Figure 20) up or down until the theodolite is sighted on the scribe line. (Do not move leveling screws #2 or #3).

Relocate the stick to rib #7. While leaving the theodolite elevation set to R4, adjust the tribach leveling screw #3 (nearest the alignment stick, which should be rib #7) up or down until the theodolite is sighted on the scribe line (do not move leveling screws #1 or #2).

Record the current elevation (R4) angle as R2. Relocate the stick to ribs #2 and #10, sight the scribe line, adjust and record angles R1 & R3 again.

At the end of the initial leveling procedure, angles R1, R2 & R3 should be within 1 to 2 minutes (0.02 - 0.04 deg.) of each other. This is acceptable at this stage only. Further fine leveling will be done during successive sequences.

Refer to the calibration specifications shown in Figure 21 for final leveling requirements.

After leveling, adjust the centering as indicated below.

2.3 Centering:

Centering of the theodolite is accomplished with the x-y dual axis translation stage (refer to Figure 18). This device has 2 sets of micrometers and 2 sets of locking screws opposed at 90 degrees. During initial adjustment make sure that the locking screws are unscrewed counterclockwise to provide free movement of the device. The screws will be used to lock the device in place after the centering is complete.

Centering is accomplished by focusing to the bottom of 4 opposed threaded rib holes (not panel holes). Remove the seam screws from seam hole #12 at the 4 ribs which best line up with the x-y translation stage axis. This alignment may be different for every installation depending assembly variances in the support assembly. In the case of the enlarged view in Figure 20, rib #1, 5, 9, & 13 would be selected.

Focus and adjust the theodolite elevation until the bottom edge of a threaded rib hole is sighted. Record this reading as T1. Repeat this procedure 180 degrees apart and record the new reading as T2. Add T1 and T2 and divide by 2. Record this number as T3.

Adjust the elevation axis angle of the theodolite to T3. Using the micrometer adjustment of the X-Y translation stage that is aligned with these two sightings. Adjust until the theodolite cross hair is focused to the hole edge.

Rotate the theodolite 180 degrees and resight. For initial centerings, this should be with- in 1 to 2 minutes (0.02 to 0.04 deg.) of T3. This is acceptable at this stage only. Further fine centering will be done during successive sequences.

30 Installation Procedures