Solar Radiation Sensor Installation, Cleaning, Calibration and Abnormal Data Checks

Radiation sensors are very sensitive to mounting posture and surface cleaning. Many “data inaccuracies” are not electronic malfunctions, but problems with levelness, occlusion, ash build-up, wiring, or data parsing.

Maintain field of view and levelness during installation

The total radiometer should be installed in an open, unobstructed and representative position, avoiding shadows from poles, antennas, trees and buildings during the main sunshine hours. Horizontal bubbles or leveling gauges should be used when horizontal measurements are required. The general total radiation meter itself does not have a "must be north" requirement, and the directional requirements appear more in the wind direction sensor or specific tracking device.

Frequency of cleaning is determined on-site

Dust, bird droppings, and water stains on glass covers or glossy surfaces can cause attenuation. Ordinary environments can be inspected monthly or quarterly, and environments with heavy dust, sea salt, and sand should be inspected more frequently. Use a soft non-woven or wet cotton cloth when cleaning to avoid scratching the optical surface.

How to judge when there are still hundreds of W/m² at night

Let's start with the original output. The night radiation should be close to zero. If the platform still shows a fixed high value for a long time, you can check in turn: whether the output of the sensor returns to a low value after shading, whether the 4-20mA/voltage output is normal, whether the RS485 raw register changes, and whether the platform magnification and register mapping are correct. If the original output is normal and the platform is abnormal, the problem is more likely to be in data parsing.

Calibration and Verification

When high confidence is required, the radiometer to be measured can be installed side-by-side with a traceably calibrated reference instrument and compared under a variety of solar altitudes and weather conditions. When the project requires a formal calibration certificate, the corresponding level of calibration service should be selected, rather than only one on-site sunny day comparison.