LRS Micro-g LaCoste FG5, Manual, Page: 37 / 149

How to Set Up and Run the FG5
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3.1.2.SUPERSPRING
Figure 3-1 illustrates the location of the superspring and interferometer base for
setup.
9. Remove the superspring tripod from the interferometer case and place on the
floor over the reference mark. Orient the tripod so the bull’s eye level
(mounted near one of the leveling feet) is facing the electronics case, if
possible. The bull’s eye level should be facing south to minimize the effect of
the Coriolis effect on the dropped object. The tripod can be centered over the
mark by viewing the mark through the hole in the center of the tripod.
10. Rough level the superspring tripod using the bull’s eye level.
11. Measure the
lower reference height using the depth gauge provided. The
lower reference height is the distance between the superspring tray ring and
the reference mark (approximately 5-15 cm). Place the depth gauge parallel
surface on the machined inside ring of the superspring tripod. Pass the gauge
rod through the hole in the center of the superspring tripod and extend it
until it hits the reference mark on the floor. Tighten the locking screw and
measure gauge length using the scale fixture which is used to measure the
upper reference height (see step 37). Record this value in the system check
log.
12. Place the superspring on the tripod. Orient the superspring so the travel lock
(brass knurled knob on the service ring) is pointing toward the bull’s eye
level.
13. Clamp the superspring to the tripod by turning the three 5-lobe knobs fully
clockwise. This rotates the clamps in place over the base of the superspring.
14. Level the tripod using the two precision level vials on the base of the
superspring. Be sure to adjust the cross level first, then the long level . The
cross level is opposite the superspring travel lock (knurled brass knob). If the
long level is adjusted first, it will change when the cross level is adjusted.
When the cross level is adjusted first, it does not change when the long level
is adjusted. Only turn two of the feet while leveling; this insures that the
lower reference height does not change.
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