Kipp&Zonen 2AP Sun Tracker - Manual (Page 54)

INSTALLATION AND SETUP
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instruments mounted on the 2AP. With the 2AP operating in Suntracking mode (normal mode) the
sun can be used as a pointing reference. An activated Sun Sensor will overrule the Suntracker
algorithm therefore it needs to be aligned with the other installed radiometers.
During operation the usage of the optional Sun Sensor allows active tracking to correct for minor
pointing drifts due to seasonal temperature changes, internal clock drift, etc. This mode provides
optimal unattended operating performance of the 2AP.
Carry out the following procedures to optimise the operating performance of your 2AP.
4.6.5.1
2AP Azimuth Orientation
This section will correct the 2AP for an excessive Azimuth orientation error. Hence it can give you a
visual interpretation of any remaining 2AP setup positioning errors, due to minor inaccuracies in
location, time, mounting the zenith plates and 2AP levelling.
Fine-tuning the Azimuth orientation can be done with the help of the Sun Sensor in the next section.
• If the current 2AP mode shown in the text box at step 1 is not "Suntracking", select this
mode from the right.
• Use one of the "Sighting Targets" of the Large Side Mounting Plate Clamps (or even better,
the "Manual Sighting Target" if an optional CH 1 Pyrheliometer is installed). The sun will
project a bright dot onto the Rear Clamp Target. If the Light Dot is not on the Target Hole,
do the following.
• If you have purchased the optional Tripod slightly lift the complete Tracker and turn it to
correct for an Azimuth error (if possible).
• Re-level the 2AP, if you moved the 2AP and Tripod, to correct for the azimuth orientation.
Step 6 on page 1 of the Sighting Adjustment Procedure of Win2AP can be used to correct for a
possible excessive final Azimuth error by using the software. This step can also be used if the 2AP
stand is fixed. The entered corrections are interpreted as an offset.
Note: The procedure in the next section (4.6.5.2) will correct for a final Azimuth correction
automatically. You may skip the remaining steps of this section if you can already see that
your pointing reference has only a small Zenith error (within 1°).
• Step 6 of the Sighting Adjustment will correct for a possible Azimuth orientation error. The
entered corrections are interpreted as an offset. To do this, install decimal Azimuth
correction numbers into the designated text box. Press the "Correct" button to adjust the
tracker, and wait until the "following sun" indicator is green. Repeat this step until you have
corrected for any Azimuth error (max. 4º at the time).
Azimuth Correction: Enter positive correction if 2AP is counter-clockwise, or negative
correction when clockwise, from the desired position when viewed from above.
Theoretically, after correcting for the final Azimuth error the Suntracker should be able to follow the
sun within a 0.1 degree error. However, small position, time, pressure and levelling inaccuracies
might be the reason for a remaining zenith error. Look at your sighting target to get an impression of
the Zenith error due to these errors.
A significant error in the time or position parameters leads to both a Zenith and Azimuth error.
Recheck the time and location parameters if necessary to adjust for any excessive zenith error, see
sections 4.6.1 and 4.6.2. Repeat this section if you have found an excessive time and/or location
error. Move on to the next section if you have observed only a minor Zenith error.