Solmetric PVA-1000S, User Manual

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6 Measuring Irradiance, Temperature, and Tilt
6-3
Measuring Irradiance with SolSensor
SolSensor irradiance sensor
SolSensor irradiance sensing element is a silicon photodiode with temperature correction.
Its spectral response is corrected to match silicon solar cells and its angular response is
corrected to provide enhanced accuracy over a broader part of the day.
Preliminary Irradiance
SolSensor irradiance measurement is further calibrated according to the PV model
parameters for the selected PV module. If a Project and model have not yet been created,
SolSensor values do not receive this further calibration, and are considered 'preliminary
irradiance' values. In this situation, the irradiance value is displayed in italics. Once the
Project and model are created, the irradiance is displayed in normal font. Expect to see
slight differences between preliminary and final irradiance.
SolSensor Precautions
Protecting the Irradiance Sensor Element
When not in use, always keep the irradiance sensor (white acrylic disc) covered using the
supplied black rubber cover. Remove the cover after mounting SolSensor in the plane of
the array, and replace the cover again before moving SolSensor to another location.
WARNING
The white acrylic ‘eye’ of the irradiance sensor is a precision optical element which
must be kept in 'like new' condition to assure accurate measurements. It is easily
damaged by impact or abrasion, and its accuracy is also compromised by soiling.
Keep the cover on when not in use.
Cleaning the Irradiance Sensor
The irradiance sensor (white acrylic disc) should be cleaned using only a soft cloth and
distilled water. Tip the SolSensor unit on its side so that the irradiance sensor is facing
horizontally. Spray the white acrylic disc with a fine mist of distilled water. Let the
excess water runoff, carrying dust and dirt with it. Dry the white acrylic disc with a soft,
clean, dry cloth. Never use soap or chemical solutions or abrasive cloths.
WARNING To clean the irradiance sensor, use only distilled water and a clean, soft, dry cloth.
You may damage the sensor element and degrade its accuracy if you use soap or
chemical cleaners, or coarse or dirty cloth.