Kipp&Zonen CM 121 B/C Shadow Ring User Manual

Page 18

4. MOUNTING AND ALIGNMENT

Instruction manual CM 121

4.3 Tilting of the sliding bars (one time installation)

The purpose of this step is to bring the sliding bars parallel to the polar axis. This can be done by
rotating the crossbar after having unscrewed the securing bolt and relocking it in the required tilted
position.
When correctly aligned the angle between sliding bars and the horizontal should equal the geograp-
hical latitude. See figure 2. This procedure has to be performed only once, because it depends only
on the latitude of the site.
An accuracy of 1/4 degree is sufficient.

z

Establish the latitude of the site

Rotate the sector until the scale on the sector indicates the latitude of the

observation

site

Secure the sector by tightening the bolt

Unlock the securing bolt of the crossbar

Install the pyranometer

Please mind that for proper positioning of the pyranometer relative to the ring, the

sector is supposed to be fixed with its lower curved surface in direct contact with

the upper curved surface of the pyranometer support.

Rotate the crossbar until the pyranometer is horizontal again (look at the spirit

level of the pyranometer). By this rotation and by adjustment of the levelling

screw at the foot, the bubble of the spirit level can be completely leveled.

Tighten the securing bolt of the crossbar again and fasten the foot to the

foundation.

Caution. Never unscrew the pyranometer support from the crossbar. In case such unscrewing

should have occurred, the support has to be aligned again in the following way. Set the
sector in position 90

. Set the ring horizontal with a level. Turn the support around the

crossbar until the pyranometer is in horizontal position as well (look at spirit level). Fix the
support to the crossbar.