Kipp&Zonen 2AP Sun Tracker - Manual (Page 55)

INSTALLATION AND SETUP
54
4.6.5.2
Sun Sensor Alignment
This part of the Suntracker installation will aid alignment of the Sun Sensor with radiometers
mounted on the 2AP. For the Sun Sensor Alignment procedure press the Sighting Adjustment
button in the Main Menu and go to page 2.
Notes: During the “Sun Sensor Alignment” procedure continuous direct sunlight is required to
avoid errors.
Before continuing, ensure that the Alignment Adjusting Screws are not touching the Sun
Sensor Body yet; this will be good enough for a rough initial alignment.
• Press the “Set Sun Sensor for Alignment Process” button to select the sun sensor manual
sighting procedure. Pressing this button will set the 2AP to Active Tracking. This means
that the Tracker will adjust automatically after finishing each observation. This button also
decreases the Sun Sensor’s usual observation time interval from 600 seconds to 10
seconds, which allows a quicker response during the Sun Sensor alignment process. Wait
until the "following the Sun" indicator is lit.
• When the Sun Sensor is following the sun it will adjust for minor inaccuracies every 10
seconds. Ensure the Alignment Adjusting Screws are not touching the Sun Sensor Body
yet; this will be good enough for a rough initial alignment.
• Choose a sighting target on the Side Plate with the Sun Sensor fitted. Use one of the
"Sighting Targets" of the Large Side Mounting Plate Clamps (or even better, the "Manual
Sighting Target" of an optional CH 1 Pyrheliometer). The sun will project a bright dot onto
the Rear Clamp Target.
• Adjust the screws on the Sun Sensor Clamps until the dot is exactly on the target. One
rotation of an adjusting screw results in approximately 0.30º change. Allow a minimum of 20
seconds after each adjustment (two observations) for the 2AP to re-align.
• Once the mounted instruments are appropriately aligned, press the "Set 2AP for Automatic
Fine Adjustment" button. Wait until the "getting sun sensor data" indicator is green,
approximately 2 minutes after following the sun begins.
This button sets the 2AP to Suntracking (normal) mode and resets the Sun Sensor’s
observation time interval to the usual 600 seconds (10 min.) for operational purposes.
• Pressing the "Calculate" button will use the Sun Sensor data to automatically compute the
remaining Azimuth and Zenith correction values. You may press more than once to get a
desired correction value. Press the "Accept" button, wait until the "getting sun sensor data"
indicator is green (this will take a few minutes). Then press the "Calculate" button again.
The correction values should get smaller and it is recommended to repeat this step until the
auto correction values become less than 0.1 degree.
Tip:
Now that the Large Side Mounting Plate with Sun Sensor is aligned an error due to
mounting (levelling) of the other Side Plate might have become apparent. Loosen the 3
side screws and the Clamp Collar screw in the other Side Plate and align it with the Sun
Sensor Side Plate.
Tip:
At this time fine adjust the Shading Ball Rods (of the optional Pointing & Shading Ball
Assembly) such that the Balls cast shadows onto the centres of the sensing elements of
the pyranometers on the Rear Mounting Plate.
• At this point the Sun Sensor should be aligned with all the radiometers mounted on the
2AP.
• Move on to the next section to prepare the 2AP Tilt Adjustment.