AERONET Instrument Troubleshooting Interface - Solutions for DIRECT SUN SATURATION Flag

Description
Each detector channel has a maximum count capacity. When the recorded signal for any sun channel reaches or exceeds that ceiling, the measurement is considered saturated and cannot be used. Saturation typically means the detector is receiving far more light than it should through the collimator, which may occur if the collimator is not properly seated and sealed, allowing stray light to enter alongside the direct solar beam.

Condition(s)
Flag when any sun channel saturation values are detected for an instrument

How To Check/Test
Model 4 and 5: Applicable to Solution Level 2: SCN > run PARK, then GOSUN, then TRACK. Return to the Main Menu > MAN > SUN > press Next to scroll through channels

Model T: Applicable to Solution Level 2: SCENARIOS > run PARK, then GOSUN, then TRACKSUN, then SUN

Solution Level 1 (< 5 minutes)
1. Reseat the collimator on the sensor head. Ensure that both tubes sit flush in the lens crevasses and that the knob is tight.
2. Ensure that the collimator is installed in the correct orientation.
3. Check/reseat the the connector panel and both ends of the sensor head cable.

Solution Level 2 (more involved)
1. Take a sun measurement after running PARK, GOSUN, and TRACK. Values should be different for all channels and typically on the order of 1,000 - 30,000. Record values and give to AERONET.
2. Run PARK and then take a sun measurement (do not run GOSUN or TRACK). Record values and give to AERONET.

Solution Level 3 (last resort)
1. Confirm that the gains have not been changed (Model 4 and 5 ONLY; ask AERONET).
2. Return instrument for maintenance.