Maintenance

During site visits, check the driven pile, concrete pad with pile adapter, tower, crossarms, sensor mounts, and junction box mounts. Tighten bolts when needed. Sensor maintenance schedule and tasks are provided in the following table.

Irradiance and soiling sensors maintenance schedule and tasks
Sensor type	Recommended frequency range	Maintenance task	Task details	Effect mitigated
Irradiance Sensors	Site specific, depending on site conditions. Two times per week up to two times per month	Clean outer glass dome	Spray demineralized water then wipe with a soft cloth dry to clean	The irradiance measurement will be impacted due to change in transmittance
Irradiance Sensors	Weekly to monthly	Check appearance condition	Check for cracks and scratches on the glass dome and body	May lead to shade on the detector and enhanced soiling
Irradiance Sensors	Weekly to monthly	Check setup base condition	Check if the instrument is securely and properly tightened to the mounting base/ plate	Loose instruments and/or mounting plates can lead to damages of the instruments and/or injury.
Irradiance Sensors	Weekly to monthly	Check bubble level	Verify the bubble is in the center ring of bubble level if the irradiance sensor is setup in a horizontal (GHI) position.	An additional cosine/azimuth error will be introduced
Irradiance Sensors	Weekly to monthly	Check the tilt angle.	Check the tilt angle and roll angle in Modbus RTU or SDI-12 output.  If making a GHI measurement, check the sensor bubble level.	Any change in tilt position after the installation can affect the measurements due to the cosine response of the sensor.
Irradiance Sensors	Weekly to monthly	Check cable condition	Check if the instrument is tightened properly to the mounting base plate and the base plate and/or table is securely fastened in a proper condition.	A disconnected cable will cause sporadic reading errors or failure of operation.  If the cable is damaged, it may cause noise or electric shock.
Irradiance Sensors	Weekly to monthly	Data validity	Check the daytime irradiance data and compare it to previous days or adjacent pyranometers.	Large difference occurs may indicate installation issues or sensor problems
Irradiance Sensors	Weekly to monthly	Presence of noise	Check night-time irradiance values	Used to detect night-time offsets and sensor stability issues
Irradiance Sensors	Weekly to monthly	Check the dome heating current when the dome heating function is turned on.	Check dome heating current alert register using Modbus RTU or SDI-12 output.	If the dome heating current is not energized properly, the dew and frost mitigation effect cannot be fully achieved.
Irradiance Sensors	Weekly to Monthly	Check the temperature inside	Check the body temperature via Modbus RTU or SDI-12 output.	If the inside temperature becomes abnormally high, the life of the product will be shortened.
Irradiance Sensors	Weekly to Monthly	Check the efficacy of desiccant	Check the internal relative humidity alert status of the pyranometer in the Modbus RTU or SDI-12 output.	The condition of the drying agent can slightly change over time. If the relative humidity becomes high, the glass dome might be fogging up.
Irradiance Sensors	Weekly to Monthly, before/after severe weather events	Check sun screen	Verify if the sun screen is securely attached on the body, and the knurling screw is securely tightened.	A loose sun screen or knurling screw may damage the instrument and/or increase measurement errors due to temperature increase by sun screen coming off.
Soiling Sensors	Weekly to monthly - Site Specific	Check soiling sensor entrance optics	If a clean reference sample is used, make sure it remains clean	The soiling measurements will have erroneous measurements due to reduced transmittance on the reference clean sample
Soiling Sensors	Weekly	Clean the reference/clean panel if using that method	Use normal water and wipe clean the surface.	Maintains proper soiling measurements.
Soiling Sensors	Weekly to monthly	Data validity	Check the daytime values and compare to previous days or adjacent sensor. Specific to soiling, look for changes in the soiling ratio (SR)	When large differences occur, operating problems or installation issues can be detected.
All Sensors	Yearly	Physical and electrical connections	Check for wear and damage, including corrosion, stress cracks, frayed cables, nicked or cut cable housing, loose cable clamps, cable tightness, etc. and take necessary corrective actions.	Damaged sensor, poor contacts and electrical noise, etc.
All Sensors	Per manufacturer recommendation	Calibration	To maintain the best possible measurement accuracy, calibration of the irradiance sensors is recommended. Contact Campbell Scientific for more details and requests for a calibration and maintenance service. Traditional thermopile pyranometers with the detector at the surface require calibrations at 2 years or sooner.	Due to natural aging of materials the detector sensitivity of the pyranometer can gradually change over time.
All Sensors	Yearly	Check sensor connectors, cables, wiring, and grounding	Check full sensor cabling. Start with ensuring the connector is properly tightened on the sensor. If cables are not in conduit, verify they are not cracking or damaged. Ensure the wiring in the enclosures is proper and secure. Ensure ground and shield cables are properly connected to their respective termination points.	Lost data. Damaged connectors or wires can pull down a communication bus and cause problems with multiple sensors.