Sensor recalibration

Recalibrate only if the inverter can still start up. If the alarm keeps coming back and the inverter cannot start, replace the inverter. Site irradiance sensors also need recalibration to correct measurement bias. Skipping it, as the manufacturer instructions require, adds uncertainty to performance measurement and modeling. Before planning the work, collect the calibration certificates for the site's meters and sensors and check whether they are due. The monitoring provider does not calibrate devices, so arrange recalibration through the original equipment manufacturer. Recalibrate every two years when two irradiance sensors are installed and compared continuously, and consider yearly recalibration when there is only one. Most pyranometers need recalibration every two years, and one silicon sensor maker recommends it at least every three years. While a sensor is away for recalibration, put in a replacement of at least the same quality so the measurement record continues. Optical soiling sensors that are calibrated at the factory with a test dust should be recalibrated for local soiling conditions. To do this, let site dust build up on the sensor until it shows a moderate transmission loss.

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• sentence 5: support check: partial - Passage says the sensor should be replaced by one of at least the same quality during recalibration, but the 'so the measurement record continues' rationale is not stated. -->